AG1980 video turns to black

[rds11]

I have an issue with a Panasonic AG1980, and I was hoping somebody could maybe identify the problem and tell me if it's something that's fixable.

The unit plays tapes perfectly at first, then after 45 minutes or so of continuous playing, the video starts to get fuzzier and fuzzier until it goes out completely. I was capturing a tape the last time it happened, and I put the last 10 seconds before the video went out on youtube :
http://youtu.be/-7kY1A4QuPA

The unit doesn't seem to run hot. If I eject the tape and put it right in, the problem returns. But if I wait a little (say 30 minutes) most of the time the video is back to normal. One time, I captured a 3 hours event without watching it, and looking at the capture after I noticed that the video went out after an hour, but then went back to normal at the 2 hours mark...

I tried another power cord (I have other AG1980 VCRs) and I can rule that out. The problem is not coming from the tape itself, as I tried a few and the issue keeps occuring regardless.

Any idea what could be wrong ?

[jagabo]

Freeze spray is your friend.

[rds11]

Thanks for the quick reply Jagabo.
I'm assuming you think it's a heat related problem ? What should I be aiming for (with the spray I mean) : the power supply, or the caps on the video board ?

[jagabo]

Since the audio keeps running (and hence the head motor, etc.) I doubt the problem is in the power supply. 45 minutes from startup to failure hints that it's something that takes quite a while to heat up. Probably something in the video processing.

[orsetto]

The video boards and PSU module in the AG1980 develop myriad problems, the older they are the worse and more expensive to fix they get. This looks like either a failing cap, or thermal expansion flexing a bad cold solder connection. These days, most every issue with every AG1980 comes down to a failing cap (or ten). Figuring out which of the countless caps went bad is the hard part.

I have six of these machines, and five have gone useless in the past year or so. The sixth has one foot in the grave. The cost estimates I'm getting to properly repair them are ridiculous: I can buy a NOS JVC DVHS for that kind of money. A shame, because when the AG1980 is up to spec it really is unbeatable for certain kinds of tapes. But the upkeep is outrageous, having reached the point of diminishing returns. Weird thing is, the slightly older AG1970 model based off the same chassis is unkillable: they just keep going and going. Apparently whatever magic they put in the 1980 to improve the video over the 1970 came at the cost of long-term reliability.

[lordsmurf]

It has bad caps.
Easy fix.
We talk about the at www.digitalFAQ.com weekly these days.
I think they're all aging now.
All of them!
I had to get 3 fixed here last year.

[Megahurts]

My experince with marginal electroltic capacitors is that they get better as they warm up. Not the other way around.

I suspect a bad connection when the board felexes with heat (tap the boards when it happens) or as jagabo sugested use freeze spray. Spray the head amp circuit and small sections of the board at a time untill the video returns.

[lordsmurf]

My experince with marginal electroltic capacitors is that they get better as they warm up. Not the other way around.

They dry out or leak.
The average lifespan is about 10-15 years, hence the seemingly universal issues with this old model.

Trust me, I know what I'm talking about here.