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#1
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
I have a Nakamichi BX-300 that recently got a new idler tire and works
like new most of the time. It runs and sounds great, but every once in a while, it behaves very strangely and I would like to know what the possible cause might be. The strange behavior always happens when the BX-300 is in "PLAY" mode. The first thing you notice when it starts to act strangely is that the digital counter no longer counts...it stays at "0000" and the individual zeroes flicker rapidly. Then, when you press "STOP" the deck stops...but then it goes back into "PLAY" mode--EVEN IF A TAPE IS NOT IN THE MACHINE. The reverse is also true: Sometimes when the deck is playing, it will stop all by itself, even if it is playing a tape in excellent shape that it has played many times before. Rewind and Fast-Forward functions do not seem to be affected. In other words, when the player is acting strange, you can go to rewind and fast-forward with no problems. My first instinct is that the logic IC is started to go crazy. But this happens so seldom that I am wondering if it might just be a loose or dirty connection somewhere. What are your thoughts? Any help will be much appreciated! I love this tape deck! |
#2
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
EADGBE wrote:
I have a Nakamichi BX-300 that recently got a new idler tire and works like new most of the time. It runs and sounds great, but every once in a while, it behaves very strangely and I would like to know what the possible cause might be. The strange behavior always happens when the BX-300 is in "PLAY" mode. The first thing you notice when it starts to act strangely is that the digital counter no longer counts...it stays at "0000" and the individual zeroes flicker rapidly. Then, when you press "STOP" the deck stops...but then it goes back into "PLAY" mode--EVEN IF A TAPE IS NOT IN THE MACHINE. The reverse is also true: Sometimes when the deck is playing, it will stop all by itself, even if it is playing a tape in excellent shape that it has played many times before. Rewind and Fast-Forward functions do not seem to be affected. In other words, when the player is acting strange, you can go to rewind and fast-forward with no problems. My first instinct is that the logic IC is started to go crazy. But this happens so seldom that I am wondering if it might just be a loose or dirty connection somewhere. What are your thoughts? Any help will be much appreciated! I love this tape deck! I will preface my answer my saying that it's a long time since I last played with a BX300, so memory may be fading, but I remember it like this:- The BX300 (and the other three-head twin capstan Nakamichis) have a tape-movement sensor that stops the transport if tape isn't moving onto the take-up spool. This is so that a jammed cassette or faulty take-up doesn't spill all the tape into the cassette well. If that sensor isn't working, or slips, then it will do what you say. The clue is in the tape counter stopping. The belt that drives the tape counter also drives the movement sensor. As I recall it, all you need to do is to change the belt on the take-up spool that drives the tape counter. When you take the old belt off, clean the drive surfaces with some alcohol (isopropyl, but failing that, Wodka) and let it dry fully. The belt isn't critical, if you can't get a proper belt, I've used a small rubber band before and it worked fine. Hope this helps S. -- http://audiopages.googlepages.com |
#3
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
Serge Auckland wrote:
EADGBE wrote: I have a Nakamichi BX-300 that recently got a new idler tire and works like new most of the time. It runs and sounds great, but every once in a while, it behaves very strangely and I would like to know what the possible cause might be. The strange behavior always happens when the BX-300 is in "PLAY" mode. The first thing you notice when it starts to act strangely is that the digital counter no longer counts...it stays at "0000" and the individual zeroes flicker rapidly. Then, when you press "STOP" the deck stops...but then it goes back into "PLAY" mode--EVEN IF A TAPE IS NOT IN THE MACHINE. The reverse is also true: Sometimes when the deck is playing, it will stop all by itself, even if it is playing a tape in excellent shape that it has played many times before. Rewind and Fast-Forward functions do not seem to be affected. In other words, when the player is acting strange, you can go to rewind and fast-forward with no problems. My first instinct is that the logic IC is started to go crazy. But this happens so seldom that I am wondering if it might just be a loose or dirty connection somewhere. What are your thoughts? Any help will be much appreciated! I love this tape deck! I will preface my answer my saying that it's a long time since I last played with a BX300, so memory may be fading, but I remember it like this:- The BX300 (and the other three-head twin capstan Nakamichis) have a tape-movement sensor that stops the transport if tape isn't moving onto the take-up spool. This is so that a jammed cassette or faulty take-up doesn't spill all the tape into the cassette well. If that sensor isn't working, or slips, then it will do what you say. The clue is in the tape counter stopping. The belt that drives the tape counter also drives the movement sensor. As I recall it, all you need to do is to change the belt on the take-up spool that drives the tape counter. When you take the old belt off, clean the drive surfaces with some alcohol (isopropyl, but failing that, Wodka) and let it dry fully. The belt isn't critical, if you can't get a proper belt, I've used a small rubber band before and it worked fine. Hope this helps S. If the takeup isn't failing, and the counter belt etc are OK, I would look at the leaf switches associated with the mode cam. They are visible from the rear of the mechanism near the reel motor. There's 3 or 4 of them all together. One or more might benefit from a bit of De-Oxit. Mark Z. |
#4
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
Thanks for the good info so far! I am pleased to hear that it might
be something as simple as a belt. But two questions continue to bother me: If it is just a belt (or dirty leaf switches).... 1) Why would the digital counter always re-set itself to "0000" when the problem occurs? 2) Why would the deck go BACK into PLAY mode when I have pressed STOP? It will go back into PLAY mode even if NO tape is inside the machine! |
#5
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
EADGBE wrote:
Thanks for the good info so far! I am pleased to hear that it might be something as simple as a belt. But two questions continue to bother me: If it is just a belt (or dirty leaf switches).... 1) Why would the digital counter always re-set itself to "0000" when the problem occurs? I can't be sure of this, but doesn't the counter reset itself if the cassette is stopped and removed? I recall that the action of the movement detector was to put the machine into the same mode as if it had been stopped manually. I admit that I am rather hazy on this point. 2) Why would the deck go BACK into PLAY mode when I have pressed STOP? It will go back into PLAY mode even if NO tape is inside the machine! I can't explain this one at all, but I do remember that I had seen a Nakamichi that did that. Wish I could be more helpful. S. -- http://audiopages.googlepages.com |
#6
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
"EADGBE" wrote in message ps.com... I have a Nakamichi BX-300 that recently got a new idler tire and works like new most of the time. It runs and sounds great, but every once in a while, it behaves very strangely and I would like to know what the possible cause might be. The strange behavior always happens when the BX-300 is in "PLAY" mode. The first thing you notice when it starts to act strangely is that the digital counter no longer counts...it stays at "0000" and the individual zeroes flicker rapidly. Then, when you press "STOP" the deck stops...but then it goes back into "PLAY" mode--EVEN IF A TAPE IS NOT IN THE MACHINE. The reverse is also true: Sometimes when the deck is playing, it will stop all by itself, even if it is playing a tape in excellent shape that it has played many times before. Rewind and Fast-Forward functions do not seem to be affected. In other words, when the player is acting strange, you can go to rewind and fast-forward with no problems. My first instinct is that the logic IC is started to go crazy. But this happens so seldom that I am wondering if it might just be a loose or dirty connection somewhere. What are your thoughts? Any help will be much appreciated! I love this tape deck! **Check the power supply regulators and associated capacitors (monitor with a logging meter). You may find a heat sensitive component. The key, for me, was the zeroing of the counter. Not much else can affect all the systems you mentioned. A CRO may pick up excessive ripple and/or noise on the rails. -- Trevor Wilson www.rageaudio.com.au -- Posted via a free Usenet account from http://www.teranews.com |
#7
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
I don't know your answer, but I have one here right now to look at-
-There is no rubber belt on the spindle to the counter. The count is derived from the opto-interrupt behind the spindle. -The counter does not reset when the door is opened. -The mode cam leaf switches are right on top of the transport mechanism right side. Very easy to access when you lift the cover. -On a unit of this age with funky logic, I'd also start with the power supply and other electrolytic capacitors. After that, you might have your work cut out for you! -I have seen mode cam motors freeze causing bizarre transport behavior. I've been able to get them working by rigging them to spin at high speed for a bit from an external supply. in article , EADGBE at wrote on 4/17/07 8:12 AM: Thanks for the good info so far! I am pleased to hear that it might be something as simple as a belt. But two questions continue to bother me: If it is just a belt (or dirty leaf switches).... 1) Why would the digital counter always re-set itself to "0000" when the problem occurs? 2) Why would the deck go BACK into PLAY mode when I have pressed STOP? It will go back into PLAY mode even if NO tape is inside the machine! |
#8
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
G Louie:
Thanks very much for your detailed response! It will be a big help as I diagnose what the problem might be.... I have a Nakamichi 682ZX coming that needs to be refurbished. I'll wait till it arrives and then I'll have a proper Nak "fix-fest"! Thanks to everyone who has responded so far...and I'm still looking for other opinions! Never can get too many! |
#9
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
In article .com,
EADGBE wrote: G Louie: Thanks very much for your detailed response! It will be a big help as I diagnose what the problem might be.... I have a Nakamichi 682ZX coming that needs to be refurbished. I'll wait till it arrives and then I'll have a proper Nak "fix-fest"! Thanks to everyone who has responded so far...and I'm still looking for other opinions! Never can get too many! FWIW The Nak 'Cassette Deck 2' has a flaw that allows spikes to zero the counter. (The fix is to slug the control line with a capacitor, detailed in an add-in sheet to the service manual.) Hence I'd suspect that something like this is happening and that noise on the control lines is confusing the logic. Hence as others have said, I'd examine the power lines, check the looming, and look for any poor connections. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
#10
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
EADGBE wrote:
I have a Nakamichi BX-300 that recently got a new idler tire and works like new most of the time. It runs and sounds great, but every once in a while, it behaves very strangely and I would like to know what the possible cause might be. The strange behavior always happens when the BX-300 is in "PLAY" mode. The first thing you notice when it starts to act strangely is that the digital counter no longer counts...it stays at "0000" and the individual zeroes flicker rapidly. Then, when you press "STOP" the deck stops...but then it goes back into "PLAY" mode--EVEN IF A TAPE IS NOT IN THE MACHINE. The reverse is also true: Sometimes when the deck is playing, it will stop all by itself, even if it is playing a tape in excellent shape that it has played many times before. Rewind and Fast-Forward functions do not seem to be affected. In other words, when the player is acting strange, you can go to rewind and fast-forward with no problems. My first instinct is that the logic IC is started to go crazy. But this happens so seldom that I am wondering if it might just be a loose or dirty connection somewhere. What are your thoughts? Any help will be much appreciated! I love this tape deck! Further to all the advice given, I found that I have a full service manual for the BX300. If you don't have one, you can download it for free from www.hifiengine.com S. -- http://audiopages.googlepages.com |
#11
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
Thanks for the tip, Serge. I already have that same download in hand.
Time to roll up my sleeves and find out what the problem is... |
#12
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
OK, here is a detailed update to tell everyone exactly what the BX-300 is doing...please consider the following seven facts... 1) If you turn the deck off and leave it alone overnight, the deck will always perform perfectly immediately after being switched on the next day. 2) However, after a few minutes of use, the deck will start to behave strangely again. This only happens SOMETIMES, not ALL the time. 3) If the deck happens to be playing, it will continue to play normally and sound fine, and the only symptom you see is the digital counter flickering and constantly re-setting itself back to "0000". 4) If you let the deck continue to play while this happens, the problem sometimes corrects itself and the counter will stop flickering and start to count normally again and the deck operates normally. 5) If you stop the deck while the counter is flickering, the deck will ALWAYS return to PLAY mode all by itself--EVEN IF NO TAPE IS IN THE DECK. This is very strange because there is a tape-sensing lever in the deck that actually PREVENTS the deck from playing if no tape is in the deck! 6) If you stop the deck while the counter is operating normally, the deck will stay stopped, just as it should. I should point out that if the deck is stopped while the counter is operating normally, then the counter NEVER begins to flicker. The counter will only begin to flicker if the deck is in PLAY mode. 7) When the counter flickers and you stop the deck and attempt to rewind or fast-forward the tape, the deck will follow the command for a few seconds, but it will always stop itself and return itself to PLAY mode. The only way to stop the deck permanently when the counter is flickering is to stop the deck and IMMEDIATELY turn the power off. |
#13
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
One more thing: The BX-300 ALWAYS operates normally when you first
turn it on, IF it has been left alone for a while. However, if it starts to behave strangely and you shut it off and then immediately turn it back on, then the strange behavior continues....does that make sense? |
#14
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
"EADGBE" wrote ...
One more thing: The BX-300 ALWAYS operates normally when you first turn it on, IF it has been left alone for a while. However, if it starts to behave strangely and you shut it off and then immediately turn it back on, then the strange behavior continues....does that make sense? Certainly suggests someting heat-related. |
#15
Posted to rec.audio.tech,uk.rec.audio,rec.audio.misc
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QUESTION: Weird Behavior - Nakamichi BX-300
On Apr 20, 2:38 pm, "Richard Crowley" wrote:
Certainly suggests someting heat-related. Thanks, Richard. I'm beginning to suspect that as well. I'll have some spare time in the next few days, and I'll start looking at it then. |
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