G07 Intermittent B+ Voltage

jeffn2

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I have a G07 monitor from my Ms. Pacman that has an intermittent issue. A prior owner did a cap kit and appears to have replaced the flyback.

Every once in awhile when I turn the game on, I get a black screen and the monitor goes into high voltage shutdown. I then toggle power a few times and eventually the CRT turns on and the game play is normal.

Yesterday the part went into HV shutdown and didn't respond to power toggling, so I decided to troubleshoot it. I followed the G07 flowchart and found the fuses OK and B+ at approximately 150V. I then un-soldered X701 and the B+ was still high. I turned the game off and on again and the B+ is now 120V and the CRT is operating normally.

This is the second time this exact same troubleshooting scenario has happened to me. I suspect that I could have a bad solder joint, but a quick look does not show anything. I will probably just reflow the joints and hope for the best.

Has anyone out there seen something similar?

Thanks!

Jeff
 
Look for broken traces and cold solder joints around the flyback. That area is very fragile. The traces and pads can break when replacing a flyback.

I would check the traces for continuity with a meter.

Ed
 
yup, go over it with your meter looking for cracks.

give the chassis a good re-flow wile you have it out.

if the problem persists and you need another set of eyes, your welcome to send it in.

Peace
Buffett
 
I had tge same problem a few months back.

Chris25810 suggested changing the 47 uf cap even though it was newer.

That and I double checked the solder reflow, and I've been fixed.
 
I re-flowed all of the solder joints and checked for continuity on the PCB traces. I did not find any opens or high resistance connections.

I put the chassis back in the cabinte and it powered up fine (Friday). Over the next few days I would randomly turn the machine off and on to check for operation. It consistently turned on! I believe it is fixed (crossing my fingers)!

Thanks for everyone's help! So far it seems like a cold solder joint was the problem.

-Jeff
 
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