Quote:
Originally Posted by platux
very interesting info
I had heard the advice to power up the tubes periodically but ignored the reasons
btw and slightly off topic, I'm also a proud owner and user of a Sony DXC-M3AP, a wonderful camera. it recently started to fail after some time in operation, picture from one tube suddenly twisted.
After much probing and ultimately swapping the coil circuits from one tube to another, and revising all the deflection electronics etc, I came to the conclusion that the focusing coil of the green tube assembly failed (short in the middle of the coil?)
I'm not sure if it's a frequent failure and what's the cause, but if you have some spare tube assembly to sell me please contact me 
I've been able to capture the moment in which it allegedly fails, in the video below
see how the part of the sensor normally not scanned gets scanned after the coil fails, how bigger gets the FOV after that
https://drive.google.com/file/d/1SJG...ew?usp=sharing
(video download button at the top right part of the google drive preview page) |
That looks almost like when I tinkered with the camera focusing! It looks like the deflection on the green is still going, but something did "go."
I second the "plug swapping," but be wary of those HV connections when the camera is live, they pack a punch!
I second checking for rotting glue, then check for blown tantalums. On mine, the electrolytics also did literally "just blow out" recently so I would check those too.
But, if I simply unplug the the Green focus on mine it goes from this:
To this:
So it does look like the green isn't "completely" gone, but again I second investigating those circuits with the help of the service manual.
Luckily the one for the M3AP is readily available so that would be a good help as well.
I did make a "Diagnosing the M3a" thread a while ago. I wouldn't mind if you hijack it, and I don't think it would be a big bump either.
http://videokarma.org/showthread.php?t=275482
If you do need someone to make comparisons, the NTSC model isn't all that different from the PAL model, so I'm happy to help.
Especially since Arc Tech's dying camera helped bring mine back to life. Least I can do is help someone else fix theirs!