WG4900 Vertical collapse?

jonathan1138

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Hi all - trying to get this Tron working - yesterday got no picture (but neck glow). Pulled the chassis, resoldered a few suspect joints. Monitor now shows a nice blue line straight down the middle.

I looked up the problem here and Modestsitt / Dokert had similar issue in the past - it was suggested to reflow points around large white resistors and shielded transistors on the chassis - just did that (they looked ok to start, but did them over again) and still an issue - blue line straight down the middle (game does 'play' though).

By the way - while re soldering the boards, TWICE around C702 (a cap i just put in) i get "sparks" which is strange isn't it?

Could this be purity / convergence rings out of adjustment by any chance - they were moved (unknowingly) and expect they need adjusting anyway.

Any advice on what to check next? Any help is appreciated.
 
That entire corner behind the flyback needs to be inspected for cold solder. Wiggle any part larger than a small resistor and watch the pads below for any movement. Reflow any that even THINK about looking iffy.

The two transistors mounted to the heat sinks in that area are for vertical deflection, and should be checked to see if they are good.

And of course inspect the area around the yoke connector. Sometimes you'll find a broken trace to one of the yoke pins...
 
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Ok - have the chassis in front of me and starting to wiggle / flow everything i can.

Here is something strange - is this a problem? I was working around C701 (1000 uf 25v) when the sparking happened - i just checked that cap (in circuit) and get a "Buzz". Others caps in circuit dont give me a buzz. Is that cap bad (i just replaced it btw)?

Attaching specs for reference if needed (page 14). Thanks guys.

http://arcarc.xmission.com/PDF_Monit... 19k4956.pdf
 
Well, pull it and check it again. Perhaps there is a shorted part or transformer in parallel that you are reading instead...
 
BRAVO guys! She lives!

Modessitt / Dokert - has anyone told you guys you rock lately? Well you do. Thanks for helping to bring this Tron back to life (got her three weeks ago completely dead). Had to tear myself away from the cab, i couldnt stop playing it....

Heres how it went down - Took the chassis back out and followed your advice (again). Pretty much flowed everything in the 300 range and then some. Was considering checking the transistors (need to be removed), but decided if it didnt work tonight i would just check that tomorrow. Turned it on, and it had a picture. Scrolling really fast from side to side. After ten minutes of messing around with Holds, got it to stabilize. Pretty happy to see the colors are near to spot on and i may not need to converge or purify (Purity?). (still need a few adjustments, it can wait till tomorrow its late now).


One thing does need attention - can you advise on the thin lines on the right side of the monitor? What could be causing that?



I2.jpg



I3.jpg



I4.jpg



I5.jpg



I6.jpg




Ok - off to updating my restoration thread AND cleaning up all this solder. Thanks again.
 
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Adjust the VERT DAMPING pot and that should make those lines go away. Also, turn the brightness down slightly. The black shouldn't glow that much. And you can adjust your VERT SIZE pot up a bit and you can make that "scratchpad RAM" line on the right side move off the screen...
 
Thanks man. Done for the night - need to clean up all the solder now (the aftermath !).

Looking forward to finishing that up tomorrow and will post final pics. Have a good night there.
 
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