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#1
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
Hi Experts,
I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF |
#2
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
RuF wrote:
Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics |
#3
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
Tim Schwartz wrote:
RuF wrote: Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics Thanks Tim. As you suggested I cleaned up all the contacts near the pickup and then reinstalled but it didn't do any good. Next I tweaked the contacts at the rear of the shell and reinstalled. That did the trick. Thanks again for your help. RuF. |
#4
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
valhealey wrote:
Tim Schwartz wrote: RuF wrote: Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics Thanks Tim. As you suggested I cleaned up all the contacts near the pickup and then reinstalled but it didn't do any good. Next I tweaked the contacts at the rear of the shell and reinstalled. That did the trick. Thanks again for your help. RuF. Seems like I spoke too soon. After copying 4 records to the HD, the right channel has now become the very weak one and the left is ok. I have tried several different records to make sure they were stereo and they were. I tweaked the R and RG contacts at the rear of the shell but that was no help. I made some measurements across the 2 RCA connectors and there was symmetry in the resistances. For example, across the two skirts the resistance was 0. From the black prong to the red prong the resistance was 2.8 ohms. From the black prong to the red skirt and from the red prong to the black skirt the resistance was 1.35 ohms. Comments appreciated |
#5
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
Tim Schwartz wrote:
RuF wrote: Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics Thanks Tim. As you suggested I cleaned up all the contacts near the pickup and then reinstalled but it didn't do any good. Next I tweaked the contacts at the rear of the shell and reinstalled. That did the trick. Thanks again for your help. RuF. |
#6
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
RuF wrote:
valhealey wrote: Tim Schwartz wrote: RuF wrote: Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics Thanks Tim. As you suggested I cleaned up all the contacts near the pickup and then reinstalled but it didn't do any good. Next I tweaked the contacts at the rear of the shell and reinstalled. That did the trick. Thanks again for your help. RuF. Seems like I spoke too soon. After copying 4 records to the HD, the right channel has now become the very weak one and the left is ok. I have tried several different records to make sure they were stereo and they were. I tweaked the R and RG contacts at the rear of the shell but that was no help. I made some measurements across the 2 RCA connectors and there was symmetry in the resistances. For example, across the two skirts the resistance was 0. From the black prong to the red prong the resistance was 2.8 ohms. From the black prong to the red skirt and from the red prong to the black skirt the resistance was 1.35 ohms. Comments appreciated RuF, If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics |
#7
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
Tim Schwartz wrote:
RuF wrote: valhealey wrote: Tim Schwartz wrote: RuF wrote: Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics Thanks Tim. As you suggested I cleaned up all the contacts near the pickup and then reinstalled but it didn't do any good. Next I tweaked the contacts at the rear of the shell and reinstalled. That did the trick. Thanks again for your help. RuF. Seems like I spoke too soon. After copying 4 records to the HD, the right channel has now become the very weak one and the left is ok. I have tried several different records to make sure they were stereo and they were. I tweaked the R and RG contacts at the rear of the shell but that was no help. I made some measurements across the 2 RCA connectors and there was symmetry in the resistances. For example, across the two skirts the resistance was 0. From the black prong to the red prong the resistance was 2.8 ohms. From the black prong to the red skirt and from the red prong to the black skirt the resistance was 1.35 ohms. Comments appreciated RuF, If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. The measurements were made with the turntable in the off position - arm on the rest. I made the same measurements on the cartridge in the shell but lying on a bench. The measurements were very similar. There appeared to be a small difference between the resistances of the windings - one was a bit closer to 1.3 than 1.35 and the other was a little on the other side of 1.35 - this was true for the cables and cartridge in place and for the cartridge in the shell on the bench. My ohmmeter has rather course graduations in that area. Today I'll test with the arm over the turntable and will check the muting switch and clean up the terminals and anything else I can see in that area. I'll be back soon. Your help is much appreciated. |
#8
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
Tim Schwartz wrote:
RuF wrote: valhealey wrote: Tim Schwartz wrote: RuF wrote: Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics Thanks Tim. As you suggested I cleaned up all the contacts near the pickup and then reinstalled but it didn't do any good. Next I tweaked the contacts at the rear of the shell and reinstalled. That did the trick. Thanks again for your help. RuF. Seems like I spoke too soon. After copying 4 records to the HD, the right channel has now become the very weak one and the left is ok. I have tried several different records to make sure they were stereo and they were. I tweaked the R and RG contacts at the rear of the shell but that was no help. I made some measurements across the 2 RCA connectors and there was symmetry in the resistances. For example, across the two skirts the resistance was 0. From the black prong to the red prong the resistance was 2.8 ohms. From the black prong to the red skirt and from the red prong to the black skirt the resistance was 1.35 ohms. Comments appreciated RuF, If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. |
#9
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
Tim Schwartz wrote:
RuF wrote: valhealey wrote: Tim Schwartz wrote: RuF wrote: Hi Experts, I have finally managed to get my 1219 going again, this time with a new Shure M97xE. It feeds into a Sony STRAV260 amplifier via RCA cables. The right channel is working fine but the left one has a very weak output. I swapped the RCA connectors at the amplifier and output behavior also swapped, so the problem is at the turntable. Under the turntable there are four connector prongs beside the muting switch. Two of the connectors are between one and two inches above the others. The pair closest to the axis of the turntable are attached to ends of the RCA cables. One of the other prongs has nothing connected and the fourth prong is connected to a ground lead that goes to the amplifier case and to the shields of the two wires that carry the output from the cartridge. Without taking the arm off, it's not easy to see into that area under the shell. Is it likely that there is a bad contact there? Comments appreciated. RuF RuF, It is possible that the muting switch is causing the problem, but not the first thing I'd suspect. Dual used among the worst RCA cables in existence, so if you have not already tried new ones, I would. The factory ones used crimped connections, and the grounds commonly go bad causing hum and bad connections. There is a similar problem with the head shell leads These can be resoldered, but you have to be VERY careful not to damage the head shell contacts. Both the cartridge and head shell ends of the 4 wires are suspect. You might want to consider a new head shell if they are still available. A new old stock head shell may have the same problems as your existing one, as the crimps have been around for many years. The contacts in the arm itself, where the head shell connects can often be corroded. Don't use a rough abrasive, as you'll remove the plating. I'd start with a cotton swab moistened (not dripping) with a contact cleaner. Do the head shell side of things too. I would then use a dry q-tip to remove as much of the cleaner as possible. To be really residue free, you could clean with alcohol. Of course, first start by being sure that the head shell leads are all going to the right places, and make sure the lugs going onto the cartridge pins are snug. If they are loose, squeeze them GENTLY with needle nose pliers or tweezers to tighten them up a bit. Be careful, if you over-tighten them, then they won't fit the pins on the cartridge any more. They can also break. Lastly, are you sure that the new cartridge is good? If you have an ohmmeter, then measure the left and right windings of the cartridge. The readings should be similar. This needs to be done with the head shell removed from the turntable, but the cartridge can still be mounted in the head shell. Regards, Tim Schwartz Bristol Electronics Thanks Tim. As you suggested I cleaned up all the contacts near the pickup and then reinstalled but it didn't do any good. Next I tweaked the contacts at the rear of the shell and reinstalled. That did the trick. Thanks again for your help. RuF. Seems like I spoke too soon. After copying 4 records to the HD, the right channel has now become the very weak one and the left is ok. I have tried several different records to make sure they were stereo and they were. I tweaked the R and RG contacts at the rear of the shell but that was no help. I made some measurements across the 2 RCA connectors and there was symmetry in the resistances. For example, across the two skirts the resistance was 0. From the black prong to the red prong the resistance was 2.8 ohms. From the black prong to the red skirt and from the red prong to the black skirt the resistance was 1.35 ohms. Comments appreciated RuF, If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. |
#10
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
RuF wrote:
If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. I think you definitely should check that area. There should be a difference in reading with the arm down. Are you sure you're reading the correct scale on your ohm meter? I couldn't remember typical DC resistances off the top of my head, so I pulled out a few old carts and got out the meter. On an assortment of Shure, Stanton and Pickering units (about five altogether), the readings ran anywhere from 1.25 to 1.5 *KILO* ohms. However, before I looked closely at the range indicator on my autoranging meter, I started to wonder what Tim was referring to. There's no way you could get any output at all if your cartridge was shorted out, which is the appearance of the readings you report. Check again. OTOH, you should be reading a dead short with the mute switch closed. Perhaps there's enough resistance in the wiring to give you a reading of 1.35 ohms--close enough--and the cart resistance is close to that reading, but in KILO ohms, and you didn't notice the difference? In the same drawer, which I've not pulled out in years, there are three NOS (never used--no idea why I have them unless it was from my days as a turntable setup tech in the 70's) Dual slide-in cartridge mounts. The contacts on all of those are pretty nasty. IMO, it would take chemicals or some serious elbow grease to make them serviceable. I'd pull yours and make doubly sure that all the contacts, including the ones on the cartridge terminals and the tonearm, are impeccably bright and shiny. There's a lot of potential for contact resistance there. jak |
#11
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
jakdedert wrote:
RuF wrote: If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. I think you definitely should check that area. There should be a difference in reading with the arm down. Are you sure you're reading the correct scale on your ohm meter? I couldn't remember typical DC resistances off the top of my head, so I pulled out a few old carts and got out the meter. On an assortment of Shure, Stanton and Pickering units (about five altogether), the readings ran anywhere from 1.25 to 1.5 *KILO* ohms. However, before I looked closely at the range indicator on my autoranging meter, I started to wonder what Tim was referring to. There's no way you could get any output at all if your cartridge was shorted out, which is the appearance of the readings you report. Check again. OTOH, you should be reading a dead short with the mute switch closed. Perhaps there's enough resistance in the wiring to give you a reading of 1.35 ohms--close enough--and the cart resistance is close to that reading, but in KILO ohms, and you didn't notice the difference? In the same drawer, which I've not pulled out in years, there are three NOS (never used--no idea why I have them unless it was from my days as a turntable setup tech in the 70's) Dual slide-in cartridge mounts. The contacts on all of those are pretty nasty. IMO, it would take chemicals or some serious elbow grease to make them serviceable. I'd pull yours and make doubly sure that all the contacts, including the ones on the cartridge terminals and the tonearm, are impeccably bright and shiny. There's a lot of potential for contact resistance there. jak Thanks Jak. I just completed an inspection and decided to resolder all 4 contacts on the RCA cables and the grounds, where they connect into the mute switch area. I couldn't tell very much about that switch, so I put everything back together again and both channels worked for about 15 mins and then the right one died way back to less than 10% of the left channel and stayed there looking almost dead - just an occasional tiny spurt. In what seems to be the mute switch there is little block - about 3/4" square and about 3/8" wide made up of layers of plastic and metal. It is into this block that all 4 connections mentioned above are made. There are also two sprung contacts from it that lie against the large plastic wheel with the small gears. This wheel is concentric with the platter. Are those two contacts the mute switch? How could I disable it for a short while to test further. The instrument I used was a GB Instruments GMT-12A and the right end of the scale has an omega. Then the numbers go 1,2,3 etc ..... up to 1K. Beyond that is the infinity symbol. The contacts at the end of the arm are shiny silver but the ones at the end of the shell, that make contact with them, are rather dull. I'll try a little metal polish on them soon and will let you know what happens. Have a great evening :-) |
#12
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
jakdedert wrote:
RuF wrote: If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. I think you definitely should check that area. There should be a difference in reading with the arm down. Are you sure you're reading the correct scale on your ohm meter? I couldn't remember typical DC resistances off the top of my head, so I pulled out a few old carts and got out the meter. On an assortment of Shure, Stanton and Pickering units (about five altogether), the readings ran anywhere from 1.25 to 1.5 *KILO* ohms. However, before I looked closely at the range indicator on my autoranging meter, I started to wonder what Tim was referring to. There's no way you could get any output at all if your cartridge was shorted out, which is the appearance of the readings you report. Check again. OTOH, you should be reading a dead short with the mute switch closed. Perhaps there's enough resistance in the wiring to give you a reading of 1.35 ohms--close enough--and the cart resistance is close to that reading, but in KILO ohms, and you didn't notice the difference? In the same drawer, which I've not pulled out in years, there are three NOS (never used--no idea why I have them unless it was from my days as a turntable setup tech in the 70's) Dual slide-in cartridge mounts. The contacts on all of those are pretty nasty. IMO, it would take chemicals or some serious elbow grease to make them serviceable. I'd pull yours and make doubly sure that all the contacts, including the ones on the cartridge terminals and the tonearm, are impeccably bright and shiny. There's a lot of potential for contact resistance there. jak Thanks Jak. I just completed an inspection and decided to resolder all 4 contacts on the RCA cables and the grounds, where they connect into the mute switch area. I couldn't tell very much about that switch, so I put everything back together again and both channels worked for about 15 mins and then the right one died way back to less than 10% of the left channel and stayed there looking almost dead - just an occasional tiny spurt. In what seems to be the mute switch there is little block - about 3/4" square and about 3/8" wide made up of layers of plastic and metal. It is into this block that all 4 connections mentioned above are made. There are also two sprung contacts from it that lie against the large plastic wheel with the small gears. This wheel is concentric with the platter. Are those two contacts the mute switch? How could I disable it for a short while to test further. The instrument I used was a GB Instruments GMT-12A and the right end of the scale has an omega. Then the numbers go 1,2,3 etc ..... up to 1K. Beyond that is the infinity symbol. The contacts at the end of the arm are shiny silver but the ones at the end of the shell, that make contact with them, are rather dull. I'll try a little metal polish on them soon and will let you know what happens. Have a great evening :-) |
#13
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
RuF wrote:
jakdedert wrote: RuF wrote: If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. I think you definitely should check that area. There should be a difference in reading with the arm down. Are you sure you're reading the correct scale on your ohm meter? I couldn't remember typical DC resistances off the top of my head, so I pulled out a few old carts and got out the meter. On an assortment of Shure, Stanton and Pickering units (about five altogether), the readings ran anywhere from 1.25 to 1.5 *KILO* ohms. However, before I looked closely at the range indicator on my autoranging meter, I started to wonder what Tim was referring to. There's no way you could get any output at all if your cartridge was shorted out, which is the appearance of the readings you report. Check again. OTOH, you should be reading a dead short with the mute switch closed. Perhaps there's enough resistance in the wiring to give you a reading of 1.35 ohms--close enough--and the cart resistance is close to that reading, but in KILO ohms, and you didn't notice the difference? In the same drawer, which I've not pulled out in years, there are three NOS (never used--no idea why I have them unless it was from my days as a turntable setup tech in the 70's) Dual slide-in cartridge mounts. The contacts on all of those are pretty nasty. IMO, it would take chemicals or some serious elbow grease to make them serviceable. I'd pull yours and make doubly sure that all the contacts, including the ones on the cartridge terminals and the tonearm, are impeccably bright and shiny. There's a lot of potential for contact resistance there. jak Thanks Jak. I just completed an inspection and decided to resolder all 4 contacts on the RCA cables and the grounds, where they connect into the mute switch area. I couldn't tell very much about that switch, so I put everything back together again and both channels worked for about 15 mins and then the right one died way back to less than 10% of the left channel and stayed there looking almost dead - just an occasional tiny spurt. In what seems to be the mute switch there is little block - about 3/4" square and about 3/8" wide made up of layers of plastic and metal. It is into this block that all 4 connections mentioned above are made. There are also two sprung contacts from it that lie against the large plastic wheel with the small gears. This wheel is concentric with the platter. Are those two contacts the mute switch? How could I disable it for a short while to test further. The instrument I used was a GB Instruments GMT-12A and the right end of the scale has an omega. Then the numbers go 1,2,3 etc .... up to 1K. Beyond that is the infinity symbol. The contacts at the end of the arm are shiny silver but the ones at the end of the shell, that make contact with them, are rather dull. I'll try a little metal polish on them soon and will let you know what happens. Have a great evening :-) I used metal polish to burnish the 4 contacts at the rear of the shell and then ttried to clean up the 4 mating contacts at the front of the arm. That was when I noticed that the contacts were embedded in what looked like a thin plastic sheet. While cleaning, the plate kept moving up and down. It was just pushed up into a slot and was kept in place by the shell. I pushed it all the way up and then attached the cartridge. On startup I had both channels working great. Fingers crossed :-) Thanks to all for the help. RuF |
#14
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
RuF wrote:
RuF wrote: jakdedert wrote: RuF wrote: If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. I think you definitely should check that area. There should be a difference in reading with the arm down. Are you sure you're reading the correct scale on your ohm meter? I couldn't remember typical DC resistances off the top of my head, so I pulled out a few old carts and got out the meter. On an assortment of Shure, Stanton and Pickering units (about five altogether), the readings ran anywhere from 1.25 to 1.5 *KILO* ohms. However, before I looked closely at the range indicator on my autoranging meter, I started to wonder what Tim was referring to. There's no way you could get any output at all if your cartridge was shorted out, which is the appearance of the readings you report. Check again. OTOH, you should be reading a dead short with the mute switch closed. Perhaps there's enough resistance in the wiring to give you a reading of 1.35 ohms--close enough--and the cart resistance is close to that reading, but in KILO ohms, and you didn't notice the difference? In the same drawer, which I've not pulled out in years, there are three NOS (never used--no idea why I have them unless it was from my days as a turntable setup tech in the 70's) Dual slide-in cartridge mounts. The contacts on all of those are pretty nasty. IMO, it would take chemicals or some serious elbow grease to make them serviceable. I'd pull yours and make doubly sure that all the contacts, including the ones on the cartridge terminals and the tonearm, are impeccably bright and shiny. There's a lot of potential for contact resistance there. jak Thanks Jak. I just completed an inspection and decided to resolder all 4 contacts on the RCA cables and the grounds, where they connect into the mute switch area. I couldn't tell very much about that switch, so I put everything back together again and both channels worked for about 15 mins and then the right one died way back to less than 10% of the left channel and stayed there looking almost dead - just an occasional tiny spurt. In what seems to be the mute switch there is little block - about 3/4" square and about 3/8" wide made up of layers of plastic and metal. It is into this block that all 4 connections mentioned above are made. There are also two sprung contacts from it that lie against the large plastic wheel with the small gears. This wheel is concentric with the platter. Are those two contacts the mute switch? How could I disable it for a short while to test further. The instrument I used was a GB Instruments GMT-12A and the right end of the scale has an omega. Then the numbers go 1,2,3 etc .... up to 1K. Beyond that is the infinity symbol. The contacts at the end of the arm are shiny silver but the ones at the end of the shell, that make contact with them, are rather dull. I'll try a little metal polish on them soon and will let you know what happens. Have a great evening :-) I used metal polish to burnish the 4 contacts at the rear of the shell and then ttried to clean up the 4 mating contacts at the front of the arm. That was when I noticed that the contacts were embedded in what looked like a thin plastic sheet. While cleaning, the plate kept moving up and down. It was just pushed up into a slot and was kept in place by the shell. I pushed it all the way up and then attached the cartridge. On startup I had both channels working great. Fingers crossed :-) Thanks to all for the help. RuF Cool, I composed a lengthy tutorial last evening, but realized I wasn't all that familiar with the innards of the Dual. I got sidetracked trying to download a manual from this http://www.vinylengine.com/news.shtml site; but couldn't get registered (confirming email not sent). I was skeptical as to whether the muting switch was your problem, but not familiar enough with the Dual guts to advise. From your post, it's not directly actuated by moving the tonearm, which would make some of the advice given spurious. You have an analog meter, which negated my 'ranging' scenario somewhat; unless you are unfamiliar with the function of the 'Range' switch on your meter. Glad you got it...hope it stays 'got'. I did think it was a headshell contact issue.... jak |
#15
Posted to rec.audio.tech
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Dual 1219 problem - weak left channel output
On Fri, 18 Apr 2008 08:03:07 -0500, jakdedert
wrote: RuF wrote: RuF wrote: jakdedert wrote: RuF wrote: If those measurements were made with the turntable in the off position, then you are measuring what should be a near short across the cables. If that is so, then you likely have a dirty muting switch or bad cables. If that measurement was made with the unit on and the arm above the record, then you've got the lowest resistance measurement I've ever heard of on a cartridge. Regards, Tim Schwartz Bristol Electronics Thanks again Tim. Your help is much appreciated. This time the measurements were made with the pickup on the record about mid point in the tracks. The results of the measurements were exactly the same as before, which would appear to suggest that there may be a problem with the mute switch. The RCA cables were installed a few months ago to replace the old 5-pin DIN plug and cable and were soldered to the same connections that were used previously. The original ground cables from the turntable are still used and are attached to the chassis of the Sony amplifier. The ground from the arm wiring is also attached to the same wires. I guess I could replace the original ground cables, if necessary. Today I'll check the muting switch and clean up the terminals and anything else I can see in that area. I think you definitely should check that area. There should be a difference in reading with the arm down. Are you sure you're reading the correct scale on your ohm meter? I couldn't remember typical DC resistances off the top of my head, so I pulled out a few old carts and got out the meter. On an assortment of Shure, Stanton and Pickering units (about five altogether), the readings ran anywhere from 1.25 to 1.5 *KILO* ohms. However, before I looked closely at the range indicator on my autoranging meter, I started to wonder what Tim was referring to. There's no way you could get any output at all if your cartridge was shorted out, which is the appearance of the readings you report. Check again. OTOH, you should be reading a dead short with the mute switch closed. Perhaps there's enough resistance in the wiring to give you a reading of 1.35 ohms--close enough--and the cart resistance is close to that reading, but in KILO ohms, and you didn't notice the difference? In the same drawer, which I've not pulled out in years, there are three NOS (never used--no idea why I have them unless it was from my days as a turntable setup tech in the 70's) Dual slide-in cartridge mounts. The contacts on all of those are pretty nasty. IMO, it would take chemicals or some serious elbow grease to make them serviceable. I'd pull yours and make doubly sure that all the contacts, including the ones on the cartridge terminals and the tonearm, are impeccably bright and shiny. There's a lot of potential for contact resistance there. jak Thanks Jak. I just completed an inspection and decided to resolder all 4 contacts on the RCA cables and the grounds, where they connect into the mute switch area. I couldn't tell very much about that switch, so I put everything back together again and both channels worked for about 15 mins and then the right one died way back to less than 10% of the left channel and stayed there looking almost dead - just an occasional tiny spurt. In what seems to be the mute switch there is little block - about 3/4" square and about 3/8" wide made up of layers of plastic and metal. It is into this block that all 4 connections mentioned above are made. There are also two sprung contacts from it that lie against the large plastic wheel with the small gears. This wheel is concentric with the platter. Are those two contacts the mute switch? How could I disable it for a short while to test further. The instrument I used was a GB Instruments GMT-12A and the right end of the scale has an omega. Then the numbers go 1,2,3 etc .... up to 1K. Beyond that is the infinity symbol. The contacts at the end of the arm are shiny silver but the ones at the end of the shell, that make contact with them, are rather dull. I'll try a little metal polish on them soon and will let you know what happens. Have a great evening :-) I used metal polish to burnish the 4 contacts at the rear of the shell and then ttried to clean up the 4 mating contacts at the front of the arm. That was when I noticed that the contacts were embedded in what looked like a thin plastic sheet. While cleaning, the plate kept moving up and down. It was just pushed up into a slot and was kept in place by the shell. I pushed it all the way up and then attached the cartridge. On startup I had both channels working great. Fingers crossed :-) Thanks to all for the help. RuF Cool, I composed a lengthy tutorial last evening, but realized I wasn't all that familiar with the innards of the Dual. I got sidetracked trying to download a manual from this http://www.vinylengine.com/news.shtml site; but couldn't get registered (confirming email not sent). I was skeptical as to whether the muting switch was your problem, but not familiar enough with the Dual guts to advise. From your post, it's not directly actuated by moving the tonearm, which would make some of the advice given spurious. You have an analog meter, which negated my 'ranging' scenario somewhat; unless you are unfamiliar with the function of the 'Range' switch on your meter. Glad you got it...hope it stays 'got'. I did think it was a headshell contact issue.... jak These Duals didn't have a mute switch problem unless the switch assy. bracket's screws loosened up. There was a constant problem with the headshell and arm contacts causing muted sound on either channel. As other posters mentioned, the rca cables were a major failure point. Another fairly common problem was the wires in the tone arm would go intermittent. Replacing these isn't a project for the inexperienced. Chuck |
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