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  #1  
09-17-2020, 06:14 AM
williamsc47 williamsc47 is offline
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Hi,

Sorry to bother you all. I'm new here so please go easy on me if I do anything annoying or break any rules . I hope I have posted in the most relevent section? I did also have a look to see if I could find an answer to my questions but cant find anything obvious. I apologise in advance if I missed any obvious answers.

Anyway, I have recently purchased a pretty nice looking JVC HR-S7955EK VCR over here in PAL land. I have inspected it inside and out and everything is very clean. I did clean the heads with some rubbing alcohol and a piece of paper (not ideal I know but was all I had) but they seemed to be spotless anyway, so either thoroughly cleaned before I got it, well looked after or both.

Everything seems to work well mechanically, but I have a bit of an issue with playback of some videos. The videos I have used are working fine on another (Aiwa) VCR I have so I can only assume the issue is with the JVC? Many videos seem to play perfectly fine on short tests.

The issue is, that when I start playback it seems to start ok, but then alternate between normal playback and a full snowy screen and loss of full sound and the play counter on the VCR also often stops counting. During this process the VCR also often flashes up the "B.E.S.T" indicator (when enabled) so seems to be trying to adjust the tracking. On an LP recording I was trying to play a similar thing happens but is accompanied by it slipping into SP mode and then back into LP mode. I am not yet sure if this happens on all LP videos as I have only found one to test so far.

Now the odd thing is (or odd to me at least) is that I seem to be able to correct these issues by doing an onscreen rewind for 10 seconds and then starting playback again. So far this usually seems to start the video playing correctly, although I am not sure how long for yet as I have not left a video running after this. When I do the onscreen rewind I get a different type of image on the screen, it's more or less black and white and a little out of frame if I remember correctly but becomes normal when starting to play again. Just to be clear, the onscreen rewind is normal again once the video starts playing correctly.

As it stands, I guess if this can be corrected by a brief rewind I can live with it, but just wanted to see if any of you VCR gurus have any idea if this is something that might soon be serious, may need a simple adjustment or what?

My initial thoughts were either the heads may be wearing out or a tracking/playback speed issue, but honestly I have no idea.

Any help in this matter would be greatly appreciated.

Many thanks

Last edited by williamsc47; 09-17-2020 at 06:27 AM.
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  #2  
09-17-2020, 09:10 AM
hodgey hodgey is online now
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The symptoms sound like there is an issue with the tracking signal. If the VCR has trouble reading the tracking signal it will not be able to align up the rotation of the video heads to the tracks on the tape, and the video will fade in and out. In the best case, it could be that the audio/tracking head is simply dirty, or that connectors on the cable connecting it to the circuit board are bit dirty. I would start with trying to clean the A/C head and cleaning and/or re-seating the ribbon cable that connects to it. If that doesn't help you may have an issue with electronics.

I think your VCR has the same mech as in this image (happened to have an image of it lying around), though it will look similar on other models
AC head JVC.jpg


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  #3  
09-17-2020, 12:05 PM
williamsc47 williamsc47 is offline
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Hi,

Thank you very much for taking the trouble to reply and for finding the photo, which is indeed more or less identical to mine.

Since your post, I have done as you have suggested and cleaned the audio and tracking heads again and also disconnected the ribbon, cleaned with rubbing alcohol and re-seated. Unfortunately, this has made no noticeable difference, the problem still persists on some videos, but seems to clear up with a few seconds of onscreen rewind.

If it is an issue with the electronics as you have suggested, what would you say the likely outlook would be? Is it something that will inevitably get worse or a problem that might remain unchanged?

I am basically just trying to work out if this is a machine that is worth keeping or sending back and trying for another? If I could either fix this or be reasonably confident the rewind trick will continue to work I would be happy to keep it. However, if its likely to deteriorate I might be better off looking elsewhere?

Thank you so much for your help so far, it is much appreciated.
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09-17-2020, 12:44 PM
latreche34 latreche34 is offline
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If it plays some tapes fine I don't see any problem with electronics, Try manual tracking by pushing P+/P- or Program Up/Program Down, some VCR's have Ch up/Ch down to access manual tracking and see if it helps, If it does it on a lot of tapes it could be miss aligned, Is the red seal broken on the tape guides?
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  #5  
09-17-2020, 01:29 PM
williamsc47 williamsc47 is offline
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Quote:
Originally Posted by latreche34 View Post
If it plays some tapes fine I don't see any problem with electronics, Try manual tracking by pushing P+/P- or Program Up/Program Down, some VCR's have Ch up/Ch down to access manual tracking and see if it helps, If it does it on a lot of tapes it could be miss aligned, Is the red seal broken on the tape guides?
Hi,

I did try the manual tracking, but it makes no difference. Not sure what red seal you mean?

Thanks
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09-17-2020, 03:31 PM
latreche34 latreche34 is offline
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Quote:
Originally Posted by williamsc47 View Post
Hi,

I did try the manual tracking, but it makes no difference. Not sure what red seal you mean?

Thanks
Red seal on tape guides, like nail polish, you have to open the VCR and observe the tape path to see if the tape running smooth with no curling on the edges.
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  #7  
09-18-2020, 06:40 PM
williamsc47 williamsc47 is offline
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Sorry for the slow reply.

The only thing I could see was what seems to be blue marker pen marks as shown in the picture:

https://ibb.co/thBkHQH

Last edited by williamsc47; 09-18-2020 at 06:44 PM. Reason: photo error
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  #8  
09-19-2020, 12:43 AM
latreche34 latreche34 is offline
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That's not what I meant, but even those blue markings indicate that someone is being in there already, Just return it if you can, aligning it to factory condition is going to be a pain without a service manual, the calibration tape and the tools required for the job.

As a last ditch try to realign those blue marks, From the picture it looks like your tracking pulses are advanced by about 9mm on the tape which could translate to several frames and a fraction of a frame. Whole frames don't affect video only audio synch, the fraction of the frame is the culprit for video.
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  #9  
09-24-2020, 12:03 PM
williamsc47 williamsc47 is offline
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Quote:
Originally Posted by latreche34 View Post
That's not what I meant, but even those blue markings indicate that someone is being in there already, Just return it if you can, aligning it to factory condition is going to be a pain without a service manual, the calibration tape and the tools required for the job.

As a last ditch try to realign those blue marks, From the picture it looks like your tracking pulses are advanced by about 9mm on the tape which could translate to several frames and a fraction of a frame. Whole frames don't affect video only audio synch, the fraction of the frame is the culprit for video.
My apologies once again for the slow reply. I have had a pretty busy week and have not had much chance to look at this any further until now. I have been contemplating whether or not to try as you suggest as I would love to get it working fully, but I think I have decided to return it instead. I don't think it would be fair to the seller to meddle with it too much before sending it back.

My thanks for the input and help though, it is appreciated
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