Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: ChadTower on January 13, 2005, 09:57:25 am
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Okay, working on a WG 7602...
It worked, but was a bit dull, when I got it. Then I plugged a JPAC, fed by an Avga, into it. POOF, no sync, nothing. I plug the jamma board back in that was there before (POW), the monitor is all screwed up now. Pincushioning, no green, etc. The JPAC must have sent a signal strong enough to toast parts that were on the edge.
I capped the monitor. That took care of everything, it seemed, except green. No green except for some out of place lines.
I look at the schematic, as well as Randy Fromm's troubleshooting flowchart. They both point to Transistors at Q2 (main board) and Q202 (neck). I take Q202 out, test it, it seems to pass fine (assuming a reading of 0 is the same as OPEN). I put Q202 back.
I take Q2 out, I get some readings from it that don't look right. I replace it with a new, matching transistor (NPN 2N3904).
I reconnect everything, power it up... nothing. No tube glow. No picture, nothing. Game plays blind.
DAMN.
So, I'm going to check the fuse, but I don't see any reason why replacing one transistor and removing/resoldering another would cause the whole thing to go dead or to blow the fuse.
Anyone have any suggestions, aside from the fuse?
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I was on the same boat as you, CAP KIT, re-solder this etc...and my final suggestion, throw it away and get a new one, thats what I did.
As I look back, I'm glad I did it. Good luck on your venture.
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It's all an academic experience for me... the knowledge I'm gaining is more valuable to me than the single monitor. If I didn't want to be able to fix these things I'd just have bought a new one.
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Okay, after having done a buttload of reading at Randy Fromm's site, I now know what I'm looking at with monitors. The heater is not glowing, but I know there's power going to it since the whine is there. I'm going to check the power supply in, but since that worked before the cap kit and nothing has been moved, plus the board works, I have no reason to believe it's not good. I am going to check the solder joints on the high voltage unit. Maybe I broke a solder joint moving the board around.
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Don't forget that the original flybacks on the k7000 series are failing like crazy now due to cracks and old age. The replacements are holding up fine.
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Would just doing a cap kit/manipulating the board cause the transformer to die all of a sudden like that? It worked fine before...
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Yes, it could. Remember that a flyback (just like any electronic component) can fail at any time for any reason.
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Thanks, I'll keep that in mind as I troubleshoot this weekend.