"distar97" wrote in message
oups.com...
Could it be the same board (with the mystery traces) is also used for
other model vcr's where the traces are actually used. Or could it be a
kind of ground trace where the intended purpose is not so apparent.

Have you considered the motor driver(drum) maybe partially failed in
that it is not delivering enough current, and in turn drum torque.

Skype_man's suggestion makes sense as well in that the power to the
drum must be clean. Sounds like it will take a bit more
checking and probing. I'll bet the driver passes the diode test since
it at least partially works. It's an interesting problem, keep us
informed of your progress. I had a similar problem years ago. Hard to
remember exactly how I fixed it.

Dennis H.



The castellated track seems to supply a tacho signal. The off "main beam"
multipole magnets on rotating must be flux cut by the castellations inducing
a low level signal. May feed a drum loading/cut out as well/instead of
monitoring drum motor current - i don't know, not followed path.

Main problem seemed to be ps problem. Caps ok.
Decided to uprate .1A biasing Tr to .2A and pass Tr from 3A to 6A and
changing 13.6V setting zener to 15V to see what happened. Much better start
up torque, checking Vs I'd put a 13V Zener in by mistake
and drive volts was less at 11.5V down from 12V. Replaced with intended 15 V
and drive V then 13.6V but very little torque.
Returned to 13V zener and no problems since, caters with rinkled tape now
without cutting out, i doubt its a permanent cure
tho - weird.

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