I am trying to rescue an old Panasonic VCR PV-7664. All functions work as intended except that the sound intermittently diminishes from time to time. It has very clean video playback, however the sound, intermittently goes near muting from time to time. I have tried with several tapes, cleaning the heads, video path, unglazed the pinch roller, adjusted the audio head bracket. No change. The problem persists. Also, the sound can be perfect, loud and clear for as long as 15 min before it looses the loudness again. The sound loss lasts for about a second or two. Than it returns to normal like never happened. I really appreciate if someone can share his wisdom on this issue. Thank you.

oedipus1 wrote in message
news

I am trying to rescue an old Panasonic VCR PV-7664. All functions work
as intended except that the sound intermittently diminishes from time to
time. It has very clean video playback, however the sound,
intermittently goes near muting from time to time. I have tried with
several tapes, cleaning the heads, video path, unglazed the pinch
roller, adjusted the audio head bracket. No change. The problem
persists. Also, the sound can be perfect, loud and clear for as long as
15 min before it looses the loudness again. The sound loss lasts for
about a second or two. Than it returns to normal like never happened. I
really appreciate if someone can share his wisdom on this issue. Thank
you.




--
oedipus1

Try changing the pinchwheel? is there slack on the capstan spindle bearing?

"oedipus1" wrote in message
news

I am trying to rescue an old Panasonic VCR PV-7664. All functions work
as intended except that the sound intermittently diminishes from time to
time. It has very clean video playback, however the sound,
intermittently goes near muting from time to time. I have tried with
several tapes, cleaning the heads, video path, unglazed the pinch
roller, adjusted the audio head bracket. No change. The problem
persists. Also, the sound can be perfect, loud and clear for as long as
15 min before it looses the loudness again. The sound loss lasts for
about a second or two. Than it returns to normal like never happened. I
really appreciate if someone can share his wisdom on this issue. Thank
you.




--
oedipus1


Sounds like perhaps the hifi audio is dropping out and reverting to linear
audio. The tape may be skewing a bit. Sometimes increasing the back tension
a bit will help.
If you can find the control track waveform, look to see if it's level is
dropping before the sound goes. If so, I would say the tape skew is pretty
well confirmed.

Mark Z.