I'm currently in the process of preparing to digitize VHS tapes, but I'm checking the equipment I have before structuring my workflow. I picked up an old Toshiba SV-950 SVHS player at a flea market a few years back. I recently fixed it by replacing a broken belt, and it's obvious there was electrical work done to it previously.
I'm having an issue with the VCR where diagonal lines move across the screen, noticeable particularly when the screen is dark. This occurs through both s-video and composite outputs, and on different sides of the room connected to different outlets. This does not occur on my Panasonic PV-8450. It also occurs with any tape I use. Switching from S-Video to composite actually flipped the diagonal lines.
Attached is a video comparing the PV-8450 and SV-950, you can see the lines particularly pronounced during the light and dark segments of the video, such as on the roof of the shed.
Additionally, I attached two images, before and after switching to the composite cable. The lines look less pronounced, but I also had tried cleaning the heads (with copy paper and 99% isopropyl alcohol) before the image was taken.
Any idea as to the problem? Thank you so much for any help!
Update: I noticed, when rewinding and playing, that the lines will go horizontally, then move until they stabilize vertically. You can see it best between :07 and :08. (this is a heavily degraded tape, but I was using it more as an example to beat up during these tests) I've cleaned the heads multiple times and it doesn't seem to be making much difference.
Oddly, I believe the SV-950 does have a TBC which is usually at least part of what gets VCRs onto the "recommended" list.
As for the diagonal lines, I believe that phenomena is seen when there are bad caps on the TBC or Y/C separation circuit on say the Panasonic AG1980. Also noticed. your audio pitch was varying rather wildly in that second shorter clip which suggests that tha Audio/Control Head might have an issue or something in that circuit. That's essentially what tells the VCR what the tape speed is (LP/EP etc), so if it's moving say an EP tape at LP speed, it's going to make the audio sound faster/higher pitched than it should be.
Also seemed like there were more small "comets" in the SV-950 compared to the Panasonic. I've heard this can be due to worn out heads or poor tape backtension. Oddly, there are almost no examples of what worn head playback looks like on YouTube which I find extremely odd given how supposedly common it is and how unfixable it is.
Also seemed like there were more small "comets" in the SV-950 compared to the Panasonic. I've heard this can be due to worn out heads or poor tape backtension. Oddly, there are almost no examples of what worn head playback looks like on YouTube which I find extremely odd given how supposedly common it is and how unfixable it is.
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I recall a video of video99.co.uk showing worn out video heads. Large comets certainly are a symptom (assuming the heads have been cleaned)
Toshiba SV-950 does not have any TBC, line or field or frame or otherwise. It's an old deck model, comparable to old non-TBC Panasonics like AG-1960.
Coming from a flea market is telling. Quality used gear almost always comes from facilities, or the original owners -- and these days, buyers of refurb'd gear (myself, VCRshop, etc) -- not random crap from yard sales, thrift stores, eBay (online flea market), etc. That's almost always junk being resold, often by recyclers and garage/storage/estate sales. This is the sort of out-of-spec, out-of-maintenance garbage found in those cheap venues. You don't even get what you pay for, it's overpriced boat anchors.
I was watching 12voltvids recently, where he also mentioned the vast amounts of botched DIY repairs now on eBay (and thrift stores, flea markets, etc -- same thing).
Lines are generally power line noise, but it can be a combination of problems.
This isn't a bad caps issue. More like wiring, heads, engineering flaws (several deck models have known interference type issues), and maybe caps on top of all that. A compound error.
Comets can be heads, but it's actually more often various interference and internal issues (like failing DOC).
This unit here is simply a POS.
Even if it can be fixed, it's really not worth the effort. You can get a really nice JVC 3800, 4800, or 5902 for $200 or less, if you need a non-TBC S-VHS VCR for something.
Certain people online criticize my "negativity" in threads like this (the world isn't all positivity and sunshine), but threads like this are a great example of negative economics, and a sinkhole of wasted time. Not a rabbit hole, but a sinkhole.
- If this is a "can I do it project", then awesome, go for it!
- But if this is "I want a cheap VCR to use", then you're on a wild goose chase, a snipe hunt, a fool's errand.
Also noticed. your audio pitch was varying rather wildly in that second shorter clip which suggests that tha Audio/Control Head might have an issue or something in that circuit. That's essentially what tells the VCR what the tape speed is (LP/EP etc), so if it's moving say an EP tape at LP speed, it's going to make the audio sound faster/higher pitched than it should be.
I noticed this too! I'm not worried about it as it doesn't appear during playback, this was due to virtualdub settings resampling the audio, pretty sure it's playing catch-up with missing frames. The tape is very poor. During normal playback the audio is just fine.
Quote:
Originally Posted by aramkolt
Also seemed like there were more small "comets" in the SV-950 compared to the Panasonic. I've heard this can be due to worn out heads or poor tape backtension.
I would not be surprised. This is a very well-loved vcr. well maintained but with heavy use. The repairs that were done to it were done professionally by a local shop, who I actually called regarding it a few years back.
Quote:
Originally Posted by aramkolt
As for the diagonal lines, I believe that phenomena is seen when there are bad caps on the TBC or Y/C separation circuit on say the Panasonic AG1980.
This is just the kind of answer I was looking for. I could see the separation of luminance and the chroma when the video was stabilizing. There's no schematic online, as it's a very rare deck, but if I find it's worth my trouble, I might try and track down the cap.
I appreciate the time you took to respond!
Quote:
Originally Posted by lordsmurf
This is the sort of out-of-spec, out-of-maintenance garbage found in those cheap venues. You don't even get what you pay for, it's overpriced boat anchors.
I paid about 15 bucks for this unit, and for that price, I got some good experience and damn good picture quality. Unfortunately I don't think I'll enjoy the time I have to sink into finding the exact cause of the issue, so I'll probably leave it at this.
Quote:
Originally Posted by lordsmurf
threads like this are a great example of negative economics, and a sinkhole of wasted time. Not a rabbit hole, but a sinkhole.
If this is a "can I do it project", then awesome, go for it!
- But if this is "I want a cheap VCR to use", then you're on a wild goose chase, a snipe hunt, a fool's errand.
I wouldn't consider this a sinkhole for me (though I understand the sentiment)! I've learned a lot, and gained valuable experience. It brought me to this forum, if that counts for anything.
If this thread appears on a search engine to anyone, I'd like to say that if you find a unit like this for cheap (like 15 dollars), and you don't mind a little time and work, pick it up. Use it to practice, or to learn a new skill. There are fewer and fewer people learning trades like appliance repair, and there only so many units left. It's better to practice on something like this instead of a nicer unit!
