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David Farber David Farber is offline
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Default Super fast REW or FF on VCR, problem, Sharp VC MH711

N_Cook wrote:
David Farber wrote in message
...

"N_Cook" wrote in message
...
Will rewind 90 percent of a 4 hour tape in 40 seconds or so and 20s
for the
remainder.
What would allow the motor to run at full tilt ? clunking loudly to
a stop.
If it was not for the "crumple zone" of tape pulled into the gap
between tape roll and spool disc then the tape would have snapped
at the end of tape.
What to look for in the way of a problem ?
System presumably monitors ratio of supply and take up rotation
rate and direction of wind and unlaces tape from drum and over 3
stepped increases ,
sets at maximum revs until the ratio goes over a preset value and
drops by stages to a slow rate until end of tape sensor acts.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/



I'm not exactly sure what you're saying is the fault. Is it that the
motor is going too fast and/or it is making a clunking noise near
the end of the tape? Newer VCR's do bump up the rewind speed after
several seconds to but I think you know that already. Is the machine
damaging the tape?

--
David Farber
David Farber's Service Center
L.A., CA



It should recognize getting close to the end of tape and start
reducing the power / revs of the motor but it once continued at full
revs to the end of tape. Been monitored by human since it happened.
It does not speed up if human stops the motor close to end, goes
normal speed to the normal clear tape auto stop if REW is engaged
again ofter pre-emptive stop.

I'm thinking a break in the line from the fast , take up spool
sensor, so less pulses coming from it and false interpretation.


Does the same thing happen when you fast forward to the end of the tape?
--
David Farber
David Farber's Service Center
L.A., CA