JVC VCR Loses Sync Every Few Seconds / Picture Scrambled

[reesclissold]

Hi All,

I recently embarked on a project to transfer some precious family videos to DVD / YouTube for my parents. These were recorded in the early-mid 90s on a VHS-C camcorder and transferred to full size VHS tape at the time.

It's taken a long time and a lot of experimenting to put together a setup that I'm happy with, and I've also used a lot of advice from this and similar forums. My capture setup consists of a JVC SR-S388E VCR with built in TBC, piped through a DVD recorder using composite (Panasonic DMR-ES10) and finally over component connection into my Elgato Game Capture HD USB device.

I've transferred hours and hours of video so far with no issues whatsoever but the JVC seems to have suddenly developed a fault - I can confirm that this is the VCR itself as it does this when hooked up to a (CRT) TV.

Basically the image seems to go out of sync every few seconds... Here's an example: https://www.youtube.com/watch?v=MdoHMjgl1Y0 (YouTube has seriously screwed up the quality with its compression but you can still see what's happening).

At first I thought it might be heat-related as I'd recently moved the VCR to a tight spot where it wasn't very well ventilated - but it still does this when positioned out in the open and even with the casing off. I'm now wondering whether it could be something that needs to be lubricated or maybe even a dying capacitor somewhere.

Having taken the lid off I can confirm that everything looks in order inside - no parts obviously damaged, dirty or broken off.

If anyone could point me in the right direction I'd very much appreciate it. I have electronics and soldering experience so I don't mind getting my hands dirty if needs be.

Thanks!

[oln]

Looks like a servo or control track issue. The VCR uses the control track on the tape to keep the tape speed in sync with the video tracks on the tape, if something goes wrong with that process, the video heads will move on and off the video tracks as the tape is pulled around.

I would maybe start with checking the cable that goes between the audio/control head (yours will look a bit different but should be easy to spot it) and the PCB, and that the A/C head is clean. If you have a scope you can also look at the ctl test point and see if it picks up a signal from the tape.

[reesclissold]

Looks like a servo or control track issue. The VCR uses the control track on the tape to keep the tape speed in sync with the video tracks on the tape, if something goes wrong with that process, the video heads will move on and off the video tracks as the tape is pulled around.

I would maybe start with checking the cable that goes between the audio/control head (yours will look a bit different but should be easy to spot it) and the PCB, and that the A/C head is clean. If you have a scope you can also look at the ctl test point and see if it picks up a signal from the tape.

Thanks so much for the detailed and helpful reply! That's exactly what I was hoping for.

I do remember seeing this component when I opened up the VCR. I also own an oscilloscope so I will see what I can see and report back.

[Brad]

Off-topic, but why use composite out of the VCR instead of S-video?

[reesclissold]

Off-topic, but why use composite out of the VCR instead of S-video?

Not at all, always grateful for advice. My understanding was that VHS tape only had a composite signal and that there was no benefit to using the S-video output. It's an S-VHS deck so I assumed the S-Video was for that type of tape. I'll certainly have a look and see if it makes a difference, thanks!

[dellsam34]

Off-topic, but why use composite out of the VCR instead of S-video?

Not at all, always grateful for advice. My understanding was that VHS tape only had a composite signal and that there was no benefit to using the S-video output. It's an S-VHS deck so I assumed the S-Video was for that type of tape. I'll certainly have a look and see if it makes a difference, thanks!

No, S-VHS and VHS are recorded exactly the same way on tape with both luminance and chrominance signals being recorded separately on the tape, S-VHS has more bandwidth allocated for the luma signal therefore more horizontal definition, So using S-Video for capturing VHS is the better way. Some people may not see a huge difference because VHS quality is noisy to begin with but trust me the difference is there.

And also take component out of the equation, keep it S-Video all the way, Altering or converting the signal from one type to another is just going to muddy up the waters.

[lingyi]

Off-topic, but why use composite out of the VCR instead of S-video?

Not at all, always grateful for advice. My understanding was that VHS tape only had a composite signal and that there was no benefit to using the S-video output. It's an S-VHS deck so I assumed the S-Video was for that type of tape. I'll certainly have a look and see if it makes a difference, thanks!

It's Laserdisc that's stored as a composite signal and best output as composite. For videotapes, unless there's something wrong with the S-Video jack, it will always provide a higher quality signal.

[reesclissold]

Thanks for the advice everyone, I'll definitely be using the s-video connector once I get this back up and running.

I spent some time looking into the audio/control head and I'm now convinced that this is the source of the problem. I have (gently) cleaned it with some isopropanol alcohol but it has made no difference. After doing some research I discovered that this is also responsible for the tape counter on the front of the machine, which isn't counting up as expected.

I'm not sure where the test point is to hook up the scope but that will be my next port of call. I can see some test points on the main board but nowhere near where the a/c connects.

[dellsam34]

If it is connected with ribbon cable just pull it out and check for corrosion in the pins, if it is a soldered wire check for cracked traces.

[oln]

And also take component out of the equation, keep it S-Video all the way, Altering or converting the signal from one type to another is just going to muddy up the waters.

Using the component out will avoid any macrovision signal the DVD-recorder might add so it's not necessarily a bad thing. The DVDR digitizes the signal so the signal type is "converted" in any case.

[dellsam34]

Using the component out will avoid any macrovision signal the DVD-recorder might add so it's not necessarily a bad thing. The DVDR digitizes the signal so the signal type is "converted" in any case.

I've read complaints some time ago from users who use component out to capture VHS that they saw chroma above normal levels that they had to use the capture card proc amp to tone them down, switching back to S-Video produced natural colors. I personally never used such method so I can't confirm or deny the complaints.

[oln]

Yeah that's possible, one would have to check each setup. I think some DVDRs may also only be able to output progressive scan or upscaled video over component which is not ideal. Just noting that using component isn't necessarily bad.