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EADGBE EADGBE is offline
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Default 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!

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Serge Auckland Serge Auckland is offline
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Default 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.

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Mark D. Zacharias Mark D. Zacharias is offline
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Default 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.


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EADGBE EADGBE is offline
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Default 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!

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Serge Auckland Serge Auckland is offline
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Default 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.



--
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Trevor Wilson Trevor Wilson is offline
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Default 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



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G Louie G Louie is offline
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Default 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!


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EADGBE EADGBE is offline
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Default 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!

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Jim Lesurf Jim Lesurf is offline
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Default 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
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Serge Auckland Serge Auckland is offline
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Default 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


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EADGBE EADGBE is offline
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Default 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...

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EADGBE EADGBE is offline
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Default 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.


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EADGBE EADGBE is offline
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Default 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?

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Richard Crowley Richard Crowley is offline
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Default 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.

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EADGBE EADGBE is offline
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Default 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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