I'm restoring a Sony EV-C500E that was heavely butchered. ( Tape basket jammed, mechanics dislodged... , mode switch broken and greasy af , contact spray all over ).
Got it all sorted and cleaned, but still has a lot of noise in the picture. Strangely (giving me hope) it shows a perfectly fine image when in pause.
I don't think it's "clogged heads" as it would take a few seconds for the heads to become clogged after I release pause. It's is immediate.
( I inspected the heads with a juweliers loupe , and can't see any obvious damage. )
I have reduced the noise by cleaning the ground lip that touches the head on top. But still there is some noise.
On the scope I can see that the Servo System Control chip is varying the voltage on pin 93 ( DRUM ACCEL ). When the voltage rises, the noise becomes worse. It's doing that at about 0,5 Hz. ( But maybe that's just bad alignment? )
Sometimes, the picture returns to normal for a sec. It is then beautifully crisp and clean, better that any deck I've used before.
[Attachment 54183 - Click to enlarge]
Image at it's worst (sorry for the lamp glaring in the back)
All the waveform in the service manual for IC002 check out.
After alignment the RF envelope looks like this:
[Attachment 54186 - Click to enlarge]
I was expecting one long continues wave, not head A outputting a lot more then head B. ?
Hopefully that this is just a thing of the head amp? Can someone tell me what to look for?
update: It's also possible the previous owner has put the vcr in "test mode 2" where one channel is disabled. I do not own the RM-95 remote, which seems necessary for changing it back.
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Last edited by wvos; 17th Jul 2020 at 14:07.