JVC HR-DVS3U no picture in play, but image in pause/FF?

[Jfeat]

I've used this JVC HR-DVS3U for a long time with no problems. Transferring a VHS video for a client, there was a "jam". Since that time i get no picture while playing but if I pause, FF, REW etc., I'll see the video. Sound is there just not the video. There's a video head cleaner device with what looks like wire ties that appear to attach to nothing. I've cleaned the heads, tried different tapes but I still have the problem.

Any Ideas on how to cure this or where to get more info?

Thanks

[lordsmurf]

Video head cleaner actually cause more damage, by merely pushing around debris, not actually removing it. Those also tend to be abrasive.

Multiple potential issues here. If after a proper cleaning -- PROPER CLEANING! -- it's still not resolved, it's not a simple head clog issues. It may be head damage.

How was it jammed, exactly? That will help you trace if the issue is in bands, gears, etc.

It may alignment, but that's have to be a really ugly jam to misalign the guides.

[Jfeat]

Thanks!

I did NOT use a head cleaning cassette,etc. I used a tech wipe and isopropyl alcohol. This model has an integrated "head cleaner" that lifts when tape is seated (see photo). I also cleaned the erase head and the A/C heads. I assume the A/C head is for audio/control.

After cleaning low and behold the tapes would play for a short time then the counter stops and the auto shutdown happens.

What should I use to clean the heads?

[lordsmurf]

Are the tapes being fed now have ANY visual defects? Inspect a tape after running it through, and rewards about a minute worth of footage (no more!). 1 min for SP, or 2 LP, or 3 SLP/EP.

[Jfeat]

Checking tapes, they show no damage (magnifying glass). It definitely seems to be with the video heads. It will start to play (counter looking normal) and the sound is good. The operation tho is a bit flaky; cant rewind or stop but can FF. Like all of the heads are not reading.

[hodgey]

Do you get no output at all in play mode, or very garbled output? (may be hard to spot without an external TBC or a CRT TV, and I don't know if the JVC blue screens on bad signal or not).

I have a cheapo hitachi that does a similar thing where there seems to be little output from one of the heads (not sure if it's the head or some electronics, it sometimes works after a while), so every other field is mostly noise in play, while ffwd seeking and pause looks mostly normal. VCRs with more than 2 heads can often use a different combination of heads for normal play and seeking/pause to achieve cleaner images in those modes, so you can end up getting something even though not all heads are working well.

Not being able to rewind or stop may suggest that there is something more wrong though, maybe the snag caused a gear to skip or broke/bent something.

[npbrown82]

While I know this thread is from a while ago, I believe it's crucial to contribute with additional insights regarding pending matters (for future Google searchers lik me . The original poster's problem appears to stem from challenges linked to the "A/C" or "audio control head." It closely resembles the "flying erase head," except this A/C is located in proximity to the pinch roller. On occasion, a simple cleaning suffices to address the issue. At other times, it might be a matter of misalignment. The problem could also be related to a damaged flex cable. In my situation, I'm quite confident that the cause lies in a faulty connector, specifically connector CN2001. I'm currently in the process of replacing it...so wish me luck. I'll update this thread in case this works for me.

Here is a great video about this issue:
https://youtu.be/FuP4hTfZ36s

[dando]

@npbrown82, did you manage to solve your problem?
I just got a DVS3 in Europe and it does not output any video (black screen). Not even menus or OSD. Audio seems fine, at least when playing VHS.
I tried both SCART to RCA, and S-Video.
Any hints on what to look at? Is some setting misconfigured?
I do not have any remote yet, if that would help, I would get one.
Kind regards,
Nikolay

[npbrown82]

So likely very different issue. Try reseating the flex cable to the rear I/0.

It can be something larger though. For some reason, the way the chassis was designed it is prone to crack the main board. The crack often occurs in a place to prevent all video out. Hopefully though you just need to reseat one flex cable.

I had several of these where the crack in the mainboard prevented all video out. Audio as I recall did work. Some boards with this crack can be repaired, others would be difficult or not worth the effort relative to value.

[dando]

@npbrown82, many thanks for your fast and informative response!
I will open the unit next week and examine.
Kind regards,
Nikolay

[npbrown82]

Hey, no problem—happy to help. I’ve rebuilt many of these and know them in and out. If you get to the point that the flex cable doesn’t work and you’re inclined to check to see if that board is cracked, feel free to reply here and I can give you some pointers.

[lordsmurf]

Quote:

Originally Posted by dando

I just got a DVS3 in Europe and it does not output any video (black screen).

When hamfisted goons operate VCRs -- or when careful users overly insert/remove cables -- the solder on the I/O block can crack, and connection is lost. So, in that cases, it's not a board-level crack, just a solder crack. I've had this happen on 9x00 HR series NTSC models.

Quote:

I tried both SCART to RCA

Those SCART adapters tend to be awful, not work. So it's actually introducing another variable here, not acting as a secondary test to the s-video.

[dando]

@npbrown82, @lordsmurf, thank you!

Please excuse my very late reply.
I opened the VCR and reseated one of the flex cables - I think this is the one to the rear I/O board.
I also took some photos of the inside.

Unfortunately, still no video output. Using the same cables and setup, my other VCR outputs video correctly.

The VCR was shipped across Europe using ground transport and I found the packaging insufficient. One of the feet of the VCR had broken off, so I guess further damage to the PCBs is not excluded.

Any further help would be greatly appreciated.

Kind regards,
Nikolay

[npbrown82]

Hey Nikolay, hope you’re doing well. As you may remember, I mentioned earlier in the thread (just reiterating here in case it helps), I’ve run into this exact issue a number of times with these units, especially when they haven’t been packed well for shipping. Given that one of the feet broke off in transit, there’s a decent chance the unit took enough impact to affect the internal boards.

I actually took one of your photos and circled the area in red and attached it. This is typically where I’ve seen the issue. If you were to take this apart - and flip the board over and look at the opposite side of that same area, there’s a good chance you might find a very fine hairline crack there.

This is a known weak point in the chassis/PCB design, and it can cause exactly what you’re seeing, loss of video (and sometimes audio as well + no blue screen)

If you’re up for taking another look inside, I’d suggest closely inspecting that underside area. The crack can be extremely subtle, so it’s easy to miss.

In some cases, this can be repaired if you’re comfortable with fine soldering: bridging traces with very thin wire and securing it (some people use nail polish to secure once traces repaired). That said, it can be pretty time-consuming, and if multiple traces are affected, it may not be worth the effort.

While improper cable insertion can sometimes play a role (as @lordsmurf mentioned), I’ve most often seen this happen due to shipping damage (there is clear damage to other parts of VCR clearly due to improper packing).

- Nate

[dando]

@npbrown82, thank you very much!

I hope you are doing well, too!
I think I am making slow but steady progress. The past months have been quite busy, as will perhaps the next ones be, however I am determined to try and repair this VCR.

I have a few new observations from this week.

1. The VCR does play miniDV tapes.
I connected my old Lenovo ThinkPad T420 with integrated FireWire 400 to the VCR. Capturing with dvgrab worked fine, although I noticed some dropped/damaged frames with dvgrab. Perhaps the same would be true for WinDV, I'd have to test. But the resulting video and audio seemed alright in my short tests.

On the contrary, capturing the same tapes using dvgrab from my JVC GR-DVL9700E miniDV camcorder seemed more stable and it had 0 dropped frames.

2. Digitizing VHS -> DV25 -> FireWire didn't work
This VCR shall support internal digitization from VHS to DV25 and then output a DV25 stream over FireWire.
This was demonstrated in the following video:
https://youtu.be/Z5vL-3kpD6Q

The model in the video is different (JVC SR-VS30), but it shall be (nearly) identical to the JVC HR-DVS3. I hope this is also very relevant for the European model I have.

Unfortunately, the resulting videos from dvgrab have black image and no audio.
My intuition is that this is perhaps due to the same damage of the main board which prevents video output to SCART/S-Video.

Today I opened the VCR again with the intention to start disassembling it and get to the main board to inspect closer.
It seems to me that taking this unit apart would be quite involved and would require removing the VHS tape mechanism and then detaching the main board from the back panel.

Is this the case and how risky is it for the tape mechanism itself?
Would you happen to have any further directions on how to proceed?

Any help would be greatly appreciated!

Kind regards,
Nikolay