I struggled a bit with whether to post this in the Capture or Hardware Repair section. My main question is whether this hardware has a glitch, and not if I have some capture setup issue. Feel free to move this to Hardware Repair section if that's a better place.
My primary reason for posting is to tap the brain power of this great community to see if others have witnessed something like this. Those who have worked on these machines or just seen a lot of them in action could be especially helpful. I hope I can get a better sense of whether this is just the nature of these machines even when properly serviced, or if I just got really unlucky despite doing everything right.
There is a color issue I've seen many times now with playback on my Panasonic AG-1980, which I've had for a couple of years now. It is specific to some EP speed recordings. I have yet to see this issue with any SP or LP recordings. For a given EP recording, it either does this 100% or 0% of the time. It can even occur on one EP recording, but not another EP recording, that are both on the same tape. It also seems independent of whether the tape has been heavily played, poorly recorded, or well preserved/recorded. It is a mystery to me as to which recordings will cause it. Switching TBC on/off or adjusting tracking has no effect. It happens with direct connection from output to TV or capture card. At first I thought it was a fluke. But with the hindsight of time, I now see the issue has been there since I got it and happens with perhaps 1/3 to 1/2 of the EP recordings I've played. These recordings have come from a lot of different machines. I have a number of "lesser" VCRs that play the same recordings without this issue. But, of course, they don't have the TBC and DNR that the 1980 has. I have tried JVC. But for EP, I really prefer Panasonic.
I have read a lot of forum posts about potential issues with this model. However, I don't think I've ever seen the specific issue I'm going to show here mentioned in any of those discussions. Or if I have heard of something like it, it was on a unit that had not been properly refurbished/recapped or had a bad Y/C board, etc. Mine was completely refurbished mechanically and electronically (yes, including the Y-C board) and came from a very reputable/experienced seller that is recommended by this forum. I've had it serviced by the same place I bought it from for an unrelated issue. So it's gone through a rigorous inspection twice now.
Despite my big disappointment with this flaw in my 1980, I've come to the conclusion thus far that I have a solid machine that happens to have a very nasty quirk on a decent % of EP recordings and that may not have any way of being resolved due to the indeterminate nature of the issue. Perhaps it's rooted in it's very complex design, combined with the fragile nature of EP recordings. Although, it is hard to accept this issue happens as often as it does on a machine so often dubbed as "the best" when it's been properly serviced. I have a few VCRs that are nowhere near "the best", and none of them have done anything like this.
I'm conflicted, and want to hold out some hope that I can find another 1980 that won't behave in this way. So, I'm considering buying another one, which would also have to come from a very reputable source. However, what I wish I could know before risking a lot of money is if this issue is rare for a refurbished unit or if this is a more common phenomenon for an otherwise healthy deck and I should not expect a high chance of this issue going away entirely by buying another one.
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The Issue:
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I've attached 4 Lagarith encoded avi files. yuvhist-1980.avi is a clip with an Avisynth YUV histogram on the right. vectorscope-1980.avi is the output from the
Virtualdub ColorTools Filter in Vectorscope mode for the same clip (with the Avisynth histogram removed). Similarly, the yuvhist-4561.avi and vectorscope-4561.avi files are the same thing, but from a Panasonic PV-4561 (a standard mid 90s run of the mill VCR, but a good one for it's class).
This clip has a lot of neutral areas, namely the greyish background and the black outfit. In the 1980 clip, you see these neutral areas drifting through various color casts. Red is one example seen here, but there are other color shifts as well. You can see the V channel shifts more to magenta side for a moment and then back. When this happens, the image has a noticeable shift to a reddish cast. Similar things happen in the U channel to either the blue or yellow side.
Focusing on the center of the 1980 vectorscope clip, notice how the color data drifts together in various directions with respect to the center of the graph. It seems like a circuit cannot keep a lock on the chroma signal.
When you observe the 4561 versions of these videos, you see the U and V channels are very stable and do not drift as you see with the 1980. I also don't notice any color shifting in the video as I do in the 1980 clip. The 4561 vectorscope is notably different from the 1980 and does fluctuate a bit in magnitude. However, I don't see it "drifting" or "shifting" with respect to the center of the graph as the 1980 is doing.
I really hope to get some responses that may help me make a more informed decision with whether to seriously consider trying my luck again on another 1980. I want to believe I just had really bad luck even though I bought from an excellent source, and this wouldn't happen to me again if I got another properly serviced machine. I feel like I've done all I can with the one I have, and I shouldn't sink more money into it. However, I know it would be maddening to get another only to find this issue is more common than I would have hoped.