GO7 repair log

Riptor

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A while back I rebuilt a pile of GO7's and I had a few that had issues so I threw them back on the shelf. Last night I decided to pull a couple and check them out. The first one was totally dead with no HV. After checking all the usual stuff I finally swapped out the filter cap as a last resort. Sure enough that was the problem, first time I found a dead filter cap.
Chassis two had a B+ of 145v and did not change with adjustment. Again, checked all the usual stuff and came up empty. Swapped out IC501, HA11244 and that fixed the problem.
 
I actually had a new filter cap in a bin, not sure where I got it from. I have 125 of the HA11244 so that was no problem.
 
yea i wish i had part of his inventory as well.

i need some stock of G07 parts. i have a couple that need repairs.

Peace
Buffett
 
I just recently added a dozen or more commonly used ic's for monitor repair. I might one day start selling cap kits but will probably never do flybacks, width coils etc.
 
I've got both complete cap kits and flybacks on hand. The cap kits are brand name caps, all hi-temp. Including ALL caps, plus R908, since it's a common failure item.
 
Chassis two had a B+ of 145v and did not change with adjustment. Again, checked all the usual stuff and came up empty. Swapped out IC501, HA11244 and that fixed the problem.

I've run into that a few times. It's to the point now that if the cap kit and reflow doesn't fix the high B+, I swap the IC (with socket) next, and that usually fixes it...
 
Got another one for you.
Flat line displayed across screen, vert deflection failure. Tested the usual culprits...ended up being R411 was open. Monitor now displays correctly but has some color issues.
 
The color issue turned out to be something simple. After reconnecting my test rig the wire for the blue broke off on the jamma connector. I turned the blue pot up and saw the monitor was displaying blue so I immediately went to the game board/harness looking for the problem.

On to the next chassis....
HV shutdown, obvious attemps of repair have been made. I found the regulator had been hooked up incorrect so I replaced it. The B+ was stuck around 130v prior and now its sitting at 145v and still wont adjust. I have checked the chassis over several times and everything looks good so far. Swapped out the flyback as a shot in the dark but no go. I might set this one aside for a few days and come back to it.
 
On to the next chassis....
HV shutdown, obvious attemps of repair have been made. I found the regulator had been hooked up incorrect so I replaced it. The B+ was stuck around 130v prior and now its sitting at 145v and still wont adjust. I have checked the chassis over several times and everything looks good so far. Swapped out the flyback as a shot in the dark but no go. I might set this one aside for a few days and come back to it.

Pull X701 and see if the picture comes up. If so replace the reg, if not replace the B+ pot.
 
Got one like this too.. Havent tried the IC yet though. Another one I had that had this problem had a bad driver transformer, so the regulator wasnt ever getting loaded. However, I can hear this one come up, then shut down so I know thats not the case here.
 
Yep, already tried that too.

Are you testing this on a tube? Or just on the bench? Every once in a while I run across one that gives high B+ on the bench (with spare yoke connected but no tube), but then it works fine when on the tube. The only thing I can think of is that it needed the degaussing coil connected...
 
I have a tube that I use specifically for testing/working on monitors on the bench.

Yeah, so do I, but sometimes it's easier to do voltage checks with it off the tube and turned over. Didn't know how you were testing it...
 
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