upgraded Wei-Ya power resistor and electrolytics!

Shupac

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A friend asked me to work on a dead 25" with a Wei-Ya chassis. The collective wisdom on KLOV suggested that the old chassis wasn't worth the time or effort to fix, so I ordered a new one (model 429H). Rather than take any chances with its cheap brand-X electrolytic capacitors, I replaced all the larger ones with Nichicons before ever turning the thing on. I also upgraded the B+ filter capacitor to a 680 uF 200 V Nichicon.

I then discovered that the horror stories about this monitor overheating are true. Within 15 minutes, R804, the 25W 140 ohm resistor in the power supply, got so hot it melted through the insulation on the nearby 120 VAC cable. Fortunately the smell of burning plastic alerted me to the problem and I was able to power the thing off before anything shorted out or caught fire.

I could not in good conscience call this monitor "fixed" and return it to my buddy knowing it has this problem -- I didn't want the poor bastard's house to burn down just because he wanted to play some Golden Tee. So I decided to try upgrading the original power resistor with a beefy 50W, 150 ohm chassis-mount resistor from Digi-Key (p/n 696-1462-ND, $3.89). This thing is a beast, big and heavy with cool-looking vanes carved in the aluminum. I soldered on a couple hefty wires, routed them to the pads where the 25W resistor had been mounted, and bolted the new resistor to the chassis heatsink. Some drilling was required.

It seems to be working. I can't attest to long-term reliability, but I can say that the 50W resistor runs cool enough that you can touch it, which gives me hope.

The picture is excellent. I hope it stays that way.
 

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I would try using a portable video generator

or floating ground signal

and not the game board signal cable.

or no signal cable hooked to it all.

and see if it still gets to hot.

Each time you turn it on you risk making it worse for the

other parts so your Zener maybe bad.

But I would see if the HOT circuit ground may be

part of the issue or PS have failed.

Your looking to isolate the power supply from the rest of chassis, so I would

remove the H.O.T and load the power supply

and check the PS again.

What's the B+ running at?

is any other parts in the PS HOT too?

Heres some more things to try.

Good Luck!
 
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