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!

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!

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

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.

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?

"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.

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.