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  #1  
09-28-2021, 09:56 PM
vhsnewb vhsnewb is offline
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I have a JVC HR-J692U that I've been using to capture old tapes. One tape seems to have damaged the VCR. I previously had to take this tape apart, to fix it after the clip that holds the leader on the spool popped off after running it through a rewinder. While I was capturing it, the VCR ground to a halt several times. When I ejected the tape after a halt, it'd be scratched. When I'd reinsert it, it still wouldn't play, but I could get it to go if I fast forwarded it a bit in a rewinder.

It appears the source of these issues is some damage the tape caused to the VCR. They're all showing up on a test tape that used to play perfectly. The VCR also squeaks now when playing, the video is blurry and distorted (e.g. the edge of my test tape is wavy when it used to be straight), and it will now grind to a halt and scratch the test tape. I've attached some images of the tape scratching and video distortion.

I have a few questions:
  1. What might have gone wrong?
  2. Is this VCR salvageable? I've emailed a local repair place, but it's a drive and the repairman says he's never seen tape scratching like in my image.
  3. How could a tape do something like this to a VCR? Is there anything I should look for before playing a tape to prevent something like this from happening again?

Scratching on tape after halt:
tape-scratching.jpg

Playback distortion (with whatever deinterlace VLC used). This tape used to play with straight edges on the picture, now the edges and picture are wavy.
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Playback distortion (without deinterlacing)
damage-deinterlaced.png



Last edited by vhsnewb; 09-28-2021 at 10:16 PM. Reason: Fix my attachments
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  #2  
09-29-2021, 03:56 AM
timtape timtape is offline
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In a way it doesnt matter what caused the problem with the VCR. It now needs repairing or replacement. When they're not working properly VCR's can scratch, stretch, mangle, tapes. The damage to picture and sound is probably permanent. Sometimes tapes can damage the VCR. It's wise not to play any important tape on a VCR unless both are in top working condition.
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  #3  
09-29-2021, 07:46 AM
hodgey hodgey is online now
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Do you have a picture of the insides of the VCR maybe? It seems like something in the tape path is not acting as it should but hard to say what without seeing it.
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  #4  
09-29-2021, 09:44 AM
latreche34 latreche34 is offline
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If the tape is scratched chances are one of the heads is chipped, you should stop putting tapes in it immediately.

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  #5  
01-15-2022, 11:41 PM
vhsnewb vhsnewb is offline
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So to give an update, I brought the VCR in question to a local TV/VCR repair place to have it checked out, and the owner said he could find no problems with the VCR, except that it was one of the dirtiest he's ever seen. He said he have it a thorough cleaning. I've now gotten around to testing it, and it appears to be working fine. The picture is much better and I don't hear any more squeaking.

I've included some captures below from the same test tape as above (but a later section that wasn't played when the VCR was having problems).

I'd been running a lot of really old tapes through this VCR, and some of them seem to have problems in the rewinder (maybe sticky shed?). Could a really dirty, gummed up tape path explain the kinds of problems I was having (including the scratching)? I'd been using a cleaning tape when I had video problems (Insignia brand from Best Buy, it has a kind of tyvek like tape that's used with a wet cleaning solution), but I'm guessing that wasn't adequate.


postclean-interlaced.jpg
postclean-interlaced.png

postclean-deinterlaced.jpg
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PS: Sorry for taking so long with the follow up. I had to tear down my setup to move to a different room, and I was only just able to put everything back together.


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  #6  
01-16-2022, 01:19 AM
latreche34 latreche34 is offline
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You have massive dot crawl around the black lines in red and blue areas, Are you using composite or S-Video? If S-Video you may want to check the design of the cable if it is coaxial or just side by side wires from Chinese knock-offs. Get Monster brand, they are cheap now since there is little demand for them, I remember when they were selling for like $120.

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  #7  
01-16-2022, 05:35 AM
RobustReviews RobustReviews is offline
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Quote:
Originally Posted by latreche34 View Post
You have massive dot crawl around the black lines in red and blue areas, Are you using composite or S-Video? If S-Video you may want to check the design of the cable if it is coaxial or just side by side wires from Chinese knock-offs. Get Monster brand, they are cheap now since there is little demand for them, I remember when they were selling for like $120.
Some S-Video cables are truly dreadful, I imagine because it's not a truly 'coaxial connection' (look at the socket!) it has been assumed it's 'just a wire' by various parties. It's not a coaxial termination by definition.

By specification, though it needs a 75Ω impedance characteristic:

Rₛ(75Ω) = Rₗ(75Ω) = Z₀(75Ω) which should transfer without reflection and at the Rₗ node be -3dB on the source. All good.

there's a lot of things that can go wrong at the nodes if there's a mismatch, namely things like dot-crawl, reflection and if the universe really conspires against you, equipment damage, however unlikely with the tiny amounts of power we're talking about here. It's a very deep and complex topic and I've skimmed over a lot of detail here.

Mild issues are most likely to be seen in the areas of greatest intensity change in the signal, for example, black/white fast transitions in Y, and why plenty of old tapes have very, very 'ghosty' white text on black backgrounds, it's simply the signal 'bouncing around' in the transmission line in most instances. On off-air recordings, the ghosts tend to be more widely spaced if it's an antenna-> VCR mismatch due to the physical length (say 30 metres) and round-trip propagation delay of the cable.

Properly designed RF cables are lossy, they should be dropping 50% of the voltage of the signal as Z, irrespective of length.

Anyway, yes, there's plenty of junk S-Video cables that generate precisely the issue you've spotted.

Last edited by RobustReviews; 01-16-2022 at 05:56 AM.
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  #8  
01-16-2022, 10:44 AM
vhsnewb vhsnewb is offline
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Quote:
Originally Posted by latreche34 View Post
You have massive dot crawl around the black lines in red and blue areas, Are you using composite or S-Video?
This VCR is composite-only. Do you think the issue is that or it is possible to get better results with better composite cables? I'm using one that I had laying around that had a much thicker yellow video cable than all the other ones I had.

Quote:
Originally Posted by latreche34 View Post
Get Monster brand, they are cheap now since there is little demand for them, I remember when they were selling for like $120.
Were those actually high-quality and well designed, but just excessively overpriced?
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  #9  
01-16-2022, 02:30 PM
timtape timtape is offline
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Quote:
Originally Posted by vhsnewb View Post
So to give an update, I brought the VCR in question to a local TV/VCR repair place to have it checked out, and the owner said he could find no problems with the VCR, except that it was one of the dirtiest he's ever seen. He said he have it a thorough cleaning. I've now gotten around to testing it, and it appears to be working fine. The picture is much better and I don't hear any more squeaking.
It's good you have a good tech who told you the truth and did only the necessary cleaning work. So often a proper clean of the VCR's entire tape path is required (not just the heads). It's basic maintenance, but in my experience often neglected.

Quote:
Originally Posted by vhsnewb View Post
I'd been running a lot of really old tapes through this VCR, and some of them seem to have problems in the rewinder (maybe sticky shed?).
I've found it hard to locate a definitive list of VHS and Beta tapes (brands and types) liable to sticky shed. It seems to be far less common in these and audio cassette tapes than in many open reel tapes, so I wouldnt assume sticky shed is the problem before exploring other more likely explanations such as a VCR needing basic cleaning and maintenance.

Rewinders can be brutal on tapes. Unlike many VCR's they dont slow the tape down when approaching the beginning or end of the tape, and neither do they stop the tape before it reaches the physical end. For a tape to become broken off at the hub should normally be rare. A leader to tape splice break is more common as the adhesive eventually fails.

Quote:
Originally Posted by vhsnewb View Post
Could a really dirty, gummed up tape path explain the kinds of problems I was having (including the scratching)? I'd been using a cleaning tape when I had video problems (Insignia brand from Best Buy, it has a kind of tyvek like tape that's used with a wet cleaning solution), but I'm guessing that wasn't adequate.
.
A really dirty VCR tape path can damage the tape (creasing, crinkling, scratching) which in turn can deposit loose tape particles back onto the tape path. Cleaning tapes can only do so much, even the wet types. They is no substitute for a thorough manual clean of the tape path including the often neglected capstan shaft and pinch roller.

I'm increasingly convinced Peter Brothers is right in recommending professional tape cleaning (as well as thorough cleaning of the VCR's tape path) for best playback. Once an important tape is damaged it may need a good professional clean to gently remove the now dislodged tape particles without damaging the surface of the tape that is still intact.

Last edited by timtape; 01-16-2022 at 02:44 PM.
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  #10  
01-16-2022, 02:55 PM
hodgey hodgey is online now
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Quote:
Originally Posted by vhsnewb View Post
This VCR is composite-only. Do you think the issue is that or it is possible to get better results with better composite cables? I'm using one that I had laying around that had a much thicker yellow video cable than all the other ones I had.
I'm not sure what you are capturing with but I would think it's more about how good the capture device (or tbc/dvd-recorder, whatever gets the composite signal from the VCR) can separate color and brightness. Most capture devices won't do a great job at it.
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  #11  
01-16-2022, 04:06 PM
latreche34 latreche34 is offline
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Quote:
Originally Posted by vhsnewb View Post
This VCR is composite-only. Do you think the issue is that or it is possible to get better results with better composite cables? I'm using one that I had laying around that had a much thicker yellow video cable than all the other ones I had.
Don't expect miracles from VCR's with composite only, Yes you can use a good composite cable and a capture card with a sophisticated comb filter but you will be about as good as what you have now. That's the reason we recommend S-VHS machines here.



Quote:
Were those actually high-quality and well designed, but just excessively overpriced?
Yes.
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playback problems, tape squealing, vcr distortion, vcr repair

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