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  1. Member
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    Hi all, I'm brand new here. I'm a bit of a novice with Umatic, but have been doing a fair amount of transfer work lately and have come across a problem with a few tapes that I haven't been able to find a solution to. I'm working with a Sony VO-5850 that's just been professionally serviced (new belts, etc), into a DPS 475, then into a Black Magic Decklink. This setup works fine for most tapes, but the issue I'm having with a few tapes is this: in playback mode, the picture is either black or snowy, though the sound plays fine. When I go into jog wheel mode, either still, forward, or reverse, the picture appears. But it goes back to black or snowy when I resume playback mode. Does anyone have a solution for this problem, with this deck? I'm thinking it's something to do with the video signal level on the tape, but if so, I don't know which trimpot (if any) to adjust to try to compensate.

    Thanks in advance for any help!
    Last edited by peahix; 31st Mar 2022 at 21:09.
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  2. Capturing Memories dellsam34's Avatar
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    Are you connecting the DPS475 to the decklink with an SDI connector or analog connectors? This is less likely to be your problem but just to rule out any analog video signal drop between the DPS475 and the card.
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    Thanks for your reply! I've tried SDI as well as various analog connections, as well as connecting the deck directly to the decklink without the DPS in the chain, all with the same result. It appears to be an issue with the tapes themselves, at least as they relate to this deck. I've tried one other deck as well, that hasn't been serviced recently, with the same result.
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  4. Capturing Memories dellsam34's Avatar
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    This sounds like the tapes you have have been recorded on a miss aligned machine, The only way of capturing them is to miss align one of the decks you have. Does the sound plays at normal speed? just to rule out a different color standard tape.
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    The sound plays fine, at the correct speed, with no distortion. I should also point out that all of these tapes are parts of sets of related tapes, where other tapes in the set (recorded at the same time and on the same equipment) play fine.
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    I should also mention that all of the tapes are raw field footage from pro TV cameras. So it's odd that one tape from the shoot plays fine, and another tape from the same shoot (shot in the same camera) doesn't.
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  7. How are you getting a video feed from the VTR? Composite? Keystrobe Dub Optimiser? Modified VTR?

    U-matic's composite has bandwidth problems and other issues before even talking about comb filters. This is on top of U-matic having issues with low chrominance carrier signals and tape tension. That's assuming the oxide layer is still there to begin with or has any signal left.

    The Leitch DPS-475/DPS-575 boxes also have some performance issues and, despite being ~20 years old, are too new to have a U-matic Dub input for extracting the chroma carrier.

    It doesn't help that Blackmagic as a company is infamous for terrible, buggy analog support with no fixes in sight. Blackmagic capture cards seem to do OK once things are digital and exactly on-spec, however. Their Media Express app is shockingly decent for tape capture as well.

    So assuming the tapes are good and you've got S-video, I'd look to modern capture hardware known for correcting unstable analog signals with a modern analog front-end, plus solid drivers, e.g. the Magewell Pro Capture AIO or Pro Capture HDMI.
    Last edited by energizerfellow; 2nd Apr 2022 at 11:26.
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    Thanks for your detailed reply! I'm using the composite out on my Sony deck. I'll look into your links, thanks!
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  9. Capturing Memories dellsam34's Avatar
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    Usefull links but none of that will address your problem, Your tapes are not tracking properly, so there is no signal to improve to begin with.
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  10. One of those times when a cheap beater analog CRT TV comes in handy to better see what's going on with the drops. If you got a PVM with X/Y offset, that would help see what's going on as well.

    If the alignment is good, it would be something like the original writing deck had a lot of hours on the heads and they were writing to a 3M tape (covered in my links above). Do the video signal meters drop out on the problem tapes?
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  11. Member Cornucopia's Avatar
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    One should never gauge tape playback video characteristics on the audio either (possible partial exception: vhs hifi audio).
    Audio heads are completely separate from the video, and are linear. They have their own alignment, but badly aligned audio heads would only exhibit lower output with slightly higher noise and/or distortion, so it wouldn't be noticeable to casual evaluation until it was greatly misaligned.

    Scott
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  12. Capturing Memories dellsam34's Avatar
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    You're missing the point, a fast audio playback could possibly mean PAL tape played in a NTSC machine, You can't get PAL video to display at normal playback but you might in fast forward mode, The OP has already ruled out a format problem.
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  13. Member Cornucopia's Avatar
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    I'm not missing anything. I didn't say anything about fast audio playback, and the OP specifically said it was normal speed with no noticeable distortion. That certainly precludes any assumptions of differing TV systems.

    No, I was saying don't judge lack of issues with audio as lack of issues with video. There is a very high likelihood that the tape is either recorded with badly aligned video heads (which can go out of whack between one recording and the next) or a buildup of particulates (tape shed?) that exhibit as non-playability during normal speed but improved playability during FF. I have seen examples of this MANY times.


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  14. Capturing Memories dellsam34's Avatar
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    Right, and the OP confirmed the audio is normal after I asked him, In troubleshooting you have to use the process of elimination otherwise it could the simplest thing and one can miss it.
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  15. Given the age of U-matic in general, along with infamously bad media like Ampex and 3M/Scotch, there's a good chance the heads on the playback machine's heads are already clogged again. Some of the links I provided earlier cover what media is known to have issues, dealing with shedding and mold, what weak signals look like on U-matic, etc.

    This is one of those times having a cheap, bottom-end analog CRT TV that's like ~14" comes in real handy (bonus points if it's a PVM with horizontal/vertical delay, aka X/Y offset, which helps for seeing what's going, plus useful for setting U-matic's skew setting on each tape). Something like a cell phone video showing one of the problem tapes being played directly into a CRT would be very helpful here.

    Originally Posted by peahix View Post
    I'm using the composite out on my Sony deck.
    You're really limiting the quality and bandwidth of your captures by doing this. Garbage in, garbage out and all that.
    Last edited by energizerfellow; 7th Apr 2022 at 01:27.
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  16. Capturing Memories dellsam34's Avatar
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    Originally Posted by energizerfellow View Post
    This is one of those times having a cheap, bottom-end analog CRT TV that's like ~14" comes in real handy (bonus points if it's a PVM with horizontal/vertical delay, aka X/Y offset, which helps for seeing what's going, plus useful for setting U-matic's skew setting on each tape). Something like a cell phone video showing one of the problem tapes being played directly into a CRT would be very helpful here.
    Sorry for going off topic a little bit, I wish I can find a way to modify a small flat panel to do that, CRT is just not for me. I sometimes come across VHS tapes that play just fine with audio (with line and frame TBC functions turned on) but there is no SP/LP/EP display on the VCR's front VFD and strangely the picture is total noise in pause, fast forward search, fast rewind search, slow search, reverse slow search, reverse playback and almost no picture when either line TBC or frame TBC or both are turned off, I would like to see the HBI and VBI sections in those different modes.
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    Maybe this will offer some clues (see video link below). I found that when the screen goes snowy, if I put the deck in search mode (with the jog wheel in pause), after a few seconds the image usually appears, and if i press play at that point, the video will play relatively cleanly for a few seconds before it goes to snow again. Does this suggest anything?

    https://youtu.be/X5VDlJhSeiY
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  18. Capturing Memories dellsam34's Avatar
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    Yes, if the uMatic has a sync pulse track then try to clean the stationary head and go from there.
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    I'm not sure if my deck has a stationary head or not. I'm mostly working with a Sony VO-5850, but I also have a Sony VO-5600.
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  20. Member Cornucopia's Avatar
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    All control track (sync pulse) and linear audio track heads are stationary, and they exist on ALL decks.

    Scott
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    OK, well I'm not sure which head it is, but keep in mind that both of my decks play other tapes just fine, and I clean all the heads I can see often.
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  22. Other than the two video heads in the drum, there's two more heads. One for control / audio along the bottom of the tape, then a second head for control along the top. The dropouts make me think all the heads could use a cleaning, again (all it takes is one play of that tape). I also wonder if the problem tapes have some combination of having been eaten at some point and re-wound, wear from being parked too long, sticky shed, and/or folding along the edge from uneven tension.

    More info over at the UK Vintage Radio Repair and Restoration Discussion Forum on this problem. Section 7-8 is probably what you're looking for.

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    Last edited by energizerfellow; 30th Apr 2022 at 23:14.
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