Sony VCR SLV-E120

[Bram Stolk]

This VCR works fine for about 5-10 minutes, after a while it slows down it's
capstan speed and continues to playback in a jerky mode with distorted sound
and picture noisebars.
All my supply voltages seems correct and Caps ESR on Powersupply are a OK.
Lack of proper documentation prevents me from trouble shooting Capstan servo
circuits. Is there anybody out there having experienced similar problem(s)
and helping me out ?

TYIA

 

[Randy Thompson]

This VCR works fine for about 5-10 minutes, after a while it slows down it's
capstan speed and continues to playback in a jerky mode with distorted sound
and picture noisebars.
All my supply voltages seems correct and Caps ESR on Powersupply are a OK.
Lack of proper documentation prevents me from trouble shooting Capstan servo
circuits. Is there anybody out there having experienced similar problem(s)
and helping me out ?

TYIA

I'm not sure how old this unit is, but Sony VCRs used to have problems
with the capstan rotor warping and rubbing against copper windings
underneath.

It produced a condition similar to what you're describing. We would
just end up replacing the capstan motor assembly in those cases. Not
much else you can do.

Randy

 

[Bram Stolk]

TY Randy,
I indeed have seen the warped PCB's holding the capstan motor stator coils
causing to interfere with its rotor and being grinded.....but that was on
older sony machines...
My problem is definitely related to an electronic servo drive rather than
mechanical...
Thanks for your response anyway