FIX: Peter Chou UK9.2A power supply

KenLayton

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Peter Chou UK9.2A screw terminal power supply (a.k.a. USP-9).

Symptom: appears inoperative or dead. Fuse good, capacitors good, transistors and diodes are good.

Cause: resistors R6 and/or R11 are bad (open). Unsolder one lead of each resistor to test these otherwise false readings will occur. Sometimes if one of these resistors is starting to go bad, the power supply may operate intermittently.

Cure: If either one of the above resistors are bad, replace BOTH of them. The originals are both 330K @ 1/2 watt carbon. It is suggested to upgrade these to the same value but in metal film versions instead of carbon.

Note: the "UK9.2A" model number is silkscreened on the foil side of the circuit board.
 
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I have one of these I need to replace (I'm not SMRT enough to repair it) anyone know where I can buy one? I searched Google to no avail. :(
 
I have one of these I need to replace (I'm not SMRT enough to repair it) anyone know where I can buy one? I searched Google to no avail. :(

Try TwistedQuarter.com. They have several varieties. They are cheap enough that is easier to buy new than to play switcher roulette with a used one.

ken
 
Betson is the official USA distributor for Peter Chou power supplies. You can buy them local at the parts counter of your local coin op distributor (usually in large cities).

Betson has a Buena Park, Calif office. There's also C.A. Robinson Company in Los Angeles.

Edit: C.A. Robinson has gone out of business now.
 
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Hmm. let me know when you get to your fixes for other types of PS's. I have one that mounts into the cab (has a fan in it) with a button on the side that is pushed through a small hole on the side of the cab. The game is Area 51 Site 4 and was working when i dropped it off at a customers (the game is now mine). They didn't plug it into a surge protector like I told them, had some home remodeling done, and the game died.

I found the PS wasn't working. Got the game home and bought another new PS. Put it in and fired it up. It ran for about 3 minutes then died. I thought it was in overload shutdown, so I shut it off for a while, then reapplied a different load to it but it won't come up. Fuse is good. Power in, but no power out.

Not sure what caused it. Haven't had time to mess with it further...
 
I had one of these in my KI cab I think. sometimes you'd power the machine on and you'd get a blank stare cause the power supply didn't fire up. was intermittent like you said. I kept it around for my supergun test rig, didn't throw it out.

I'll have to check if it's the same one you're talking about, cause it was a grey Peter Chou screw terminal one :p

did they ship with Midway's games before they switched to the non-iso'd cabs?
 
I had one of these in my KI cab I think. Sometimes you'd power the machine on and you'd get a blank stare cause the power supply didn't fire up. It was intermittent like you said.

Did they ship with Midway's games before they switched to the non-iso'd cabs?

I think they did.
 
Hey, just wanted to say thanks Ken! I tinkered with 2 switchers for hours with no avail. Gotta pull those legs! This repair fixed both! One had both R6 and R11 shot, other just one of them.
 
I've seen more of these lately with those resistors going bad. I check the transistors first to make sure they aren't shorted. If they test ok then I go straight to those resistors to test them. Naturally I also test the electrolytic capacitors to see if they are ok.

My other power supply repair guides are located here:

http://home.comcast.net/~mtpacifico/_kenskorner/kenskorner.html
 
Thank you Ken for providing this information. My PSU is model USP-11-200XT and has 270K Ohm 1/2 watt resistors, but both were labeled the same on the PCB, R6 and R11.

One was open and one had a wrong reading. Got my PSU back up and running after replacing both resistors. Happy camper again:)
 
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