Odd Issue I'm Having With a VCR

[WCV82]

I have a late 1990s JVC VCR that occasionally acts up in a strange way. When I play a tape (no matter the speed SP or EP) the video works for 2-3 seconds then black screen then video works then black screen on and on for a loop. The audio is unaffected, just the video has those issues. I've run a dry head cleaner and the head cleaner tape has the same issue I just described. In the past this VCR would have this same malfunction but only on a home recorded VHS where the speed switches from EP to SP or SP to EP, but never on commercially recorded SP tapes.

So is this a video head issue or possibly some jam in the tape path? Should I just pop the top on the VCR and clean everything and hope for the best?

[damen]

I've never seen a bad video head cause a black screen.

[old_tv_nut]

Any other symptoms? is the picture stable the whole time? Does this happen with tapes you recorded on this machine, or only commercial tapes (possibly a Copyguard problem)?

[redk9258]

What model is the VCR? Maybe a power supply issue? Do you have a scope? If so, check the DC voltages for ripple.

[WCV82]

Originally Posted by redk9258

What model is the VCR? Maybe a power supply issue? Do you have a scope? If so, check the DC voltages for ripple.

Model is JVC HR-A57U

[WCV82]

Originally Posted by old_tv_nut

Any other symptoms? is the picture stable the whole time? Does this happen with tapes you recorded on this machine, or only commercial tapes (possibly a Copyguard problem)?

At this point its doing this with any tapes I pop in, either home recorded or commercial tapes, also the time code does not advance which is weird. The time code only advances when I hit the Fast Forward button. Sometimes the tape will play normally if I hit the Fast Forward button for a few minutes, but not often at this point.

[redk9258]

Is the audio / control head clean?

[themaster1]

Just do serious MANUAL cleaning of the tape path
* Qtip + alcohol (IPA 90%)on the capstan shaft, pinch roller, rollers/guides and more importantly THE DOUBLE STATIC HEAD on the right side (for audio mono and control track)

* Print paper + alcohol (IPA 90%) on the head drum (press gently, rotating counter clockwise with your other hand, do a few spins, check for black oxyde residue, continue until there is none)

[WCV82]

So I did yet another cleaning and I'm still having the same issue as before, I took a short video of the issue which may be easier than explaining it, basically every 15-20 seconds it does this loop of clear picture then tracking issues:

https://youtu.be/Ih-cJqKykz0

I've been looking for a PDF of the service manual for the VCR I have (JVC HR-A57U) but the only site its on is one that has it as a questionable ZIP file format which my antivirus did not trust.

[redk9258]

Can't view the video, It is set to private.

[WCV82]

Try this link

https://youtu.be/Ih-cJqKykz0 (it should be unlisted now and not private)

I did finally find the service manual so at least I have that to work with now.

[themaster1]

Assuming everything is clean now ; What happen if you put it in manual tracking mode (pressing Pr+ /- together) and adjust the tracking (+ or -) until you get a good picture+ sound ? More stable ?

[redk9258]

Can you watch the tape as it runs? Does it seem stable or walking up or down? You mentioned that the time stops counting when it acts up. I would watch the tape run across the control head. Does it run true? Are all of the guides tight?