Playback issues on JVC HR-S7860EK

[mrwassen]

I am having issues with a recently purchased HR-S7860EK. Some but not all PAL tapes I play on it have issues whereby the picture quality cycles from near perfect to horizontal noise/lines. The cycle is very regular about 1-2 secs. per "cycle". I have attached a very short sample of the issue (rendered as a fairly low quality mp4 just to avoid taking up too much space on the site).

The very same tapes play nearly perfectly on a HR-S7500EK I have which ironically has no TBC or other bells and whistles. This leads me to believe that the 7860 requires some sort of adjustment/maintenance.

I tried to turn on and off various combinations of TBC, "Video Stabilizer' and "B.E.S.T" as well as turned off automatic tracking and tried to adjust tracking manually, but in all cases I am having the above described cycling noise on the 7860.

It seems the issue is more prevalent on SP recordings.

Any suggestions welcome.

[themaster1]

As you said it's cycling, coming back & forth. I'm thinking: motor (wobble) or gear (missing teeth) but it's was probably into the camcorder so how to fix that...

[hodgey]

It looks like the tracking signal is missing so the vcr isn't locking on to the video on tape at all. That could be caused by a bad cable, dirty connections, very worn, dirty and/or misaligned control/audio head or electronic issues. If the same tape plays totally fine on the S7500 and other VCRs that points to a VCR rather than recording issue (unless it's the very rare case of the original recording and the S7500 having a very similar misalignment or something.) Especially since the S7500 and S7860 as far as I know use very similar mechanisms.

maybe first things I would try is cleaning the audio/control head with q-tip or similar + alcohol, and re-seating the cable that goes to it a few times.

Another thing that could maybe help with diagnosis if that doesn't help is to if audio playback (linear, not hi-fi stereo) sounds different between the decks as that could indicate difference in Audio/control head alignment or wear, and maybe post the clips. Since control track and linear/mono/standard audio goes via the same head and cable bundle so there can often be some overlap between issues. Check with a tape section that isn't dropping out (as that will probably have warbly audio due to the lack of tracking).

I have experienced the occasional loss of tracking on the related Philips VR1100 (which is mostly the same as the JVC HR-S78xx decks.) so maybe it was a similar issue.

[mrwassen]

Your input is much appreciated. I will spend some time trying your suggestions this weekend and revert with the outcome.

[mrwassen]

I think your diagnosis was right on the money. After I cleaned the audio / control head i noticed that the head seemed to be sitting a bit too low relative to the tape I had in the deck. So with the tape playing, I started slightly adjusting the 3 screws at the bottom of the head mount which enabled me to slightly adjust the head height and angle until the issue went away. (I have attached a couple of pix, one a close-up of the 3 screws and another showing the glorious end result).

Needless to say I was excited to get this working again - thanks for your help getting this resolved (not to mention the learning aspect of this exercise :-)