Wells Gardner 25K74xx with jumpy picture

[modessitt]

If you don't care about time, send it to me. I'm still behind, and it might take a couple months, but it's worth a shot. If nothing else, I'll just start swapping parts from a known good one until it's fixed...

 

[smalltownguy2]

If you don't care about time, send it to me. I'm still behind, and it might take a couple months, but it's worth a shot. If nothing else, I'll just start swapping parts from a known good one until it's fixed...

You willing to put your repair reputation on the line for this one? Others have tried and failed.....

 

[modessitt]

I don't do it for free, but I've had a lot more experience with these models than most...

 

[smalltownguy2]

Eh, don't sweat it. IF you can fix it, I'll pay you.

IF you can fix it

 

[modessitt]

No problem. Obviously an issue with the horizontal hold or horizontal position circuit...

 

[modessitt]

No problem. Obviously an issue with the horizontal hold or horizontal position circuit...

This chassis appears to be fixed.

So - I went back and reread the old threads on it, had an idea on which part of the circuit was the problem, went through the 3 or 4 parts in that circuit, changed out one tiny part that I couldn't test, and it's fixed. It's been running stable for the past 30 minutes. I'll let it run a bit longer to make sure, then test it again tomorrow night.

The culprit? Well, I figured the problem was instability in the horizontal position circuit. Since a new remote and U701 had already been tried, I checked the circuit between the two:

R713 checked out at 2.2k-ohm, but I didn't have anything that would check the 1500pf cap. What I did have tried to tell me it was a 33nf cap. So, I replaced it. BOOM - steady picture.

PS - too bad it took so long for the last guy (P&L?) to ship it to me...

 

[smalltownguy2]

Wait, so you're telling me that the issue was a bad cap??

 

[modessitt]

Wait, so you're telling me that the issue was a bad cap??

Yep. The little yellow chicklet cap seen here with "152" on it.

And it wasn't solder or anything. I put the old one back in and the problem came back...

 

[mecha]

mod, the 152 on the cap, does that mean 1500?

 

[modessitt]

It means "1-5-(2 zeroes) picofarads", or 1500 picofarads, or 1.5 nanofarads, or .0015 microfarads...

 

[mecha]

It means "1-5-(2 zeroes) picofarads", or 1500 picofarads, or 1.5 nanofarads, or .0015 microfarads...

I figured the 1500 obviously, are there any other markings on those? I dread ever having to work on a chassis where any of those are bad heh

I suppose that's what the parts sheet is for though I guess. are those functionally the same as those little box caps on the Hantarex Polos then?

 

[smalltownguy2]

Bump. This chassis is finally in my garage. I will be test firing it this weekend.

A nearly 2 year old saga should be coming to a close...

 

[smalltownguy2]

Just realized I never closed out this thread. I test fired the monitor on my buddy's Killer Instinct, and everything is perfect. I was finally able to reclaim my donor K7xxx chassis I lent him while the repair was being done.

2 years, 6 techs. 5 Cities. This chassis has put on some mileage. The US Postal service has made about $100 in shipping alone on this bad boy.

Props to Modessitt for not giving up. He wins the award on this one. Your reputation is safe with me!