UMK3 Repair Logs

zenomorp

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Nothing too fancy. Fixed 3 UMK3 boards tonight and thought I'd share what I did.

BOARD A - No Video, No Audio

-) Reseated the graphics chips (U45, U47). Video now functions as advertised.
-) Pressed down on the audio processor and the sound came on until I leg go of the pressure on it. Inspected the legs and found no issues. Reseated the chip next to the processor (U57). Audio now functions as advertised.

BOARD B - Totally Dead

-) Re-seated the revision roms. Board booted up and now works 100%.

BOARD C - All Roms Fail Test (All Red)

SAM_2799.jpg


-) Found numerous bent socket feet on the solder side of the board...

SAM_28021.jpg


Strightened socket feet. Roms now all check good (green) and board functions 100% with no defects noted.

SAM_2806.jpg


That's all folks. Hopefully this helps someone.
 
man you get easy fixes. nice job

btw that soundboard you had with 6 or 8 bong sounds, check the clock crystal at Y1 if it was a mk1 i don't remember vid was to long, bring on the vids of WWF/NBA Jam
 
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lol, they're coming.


man you get easy fixes. nice job

btw that soundboard you had with 6 or 8 bong sounds, check the clock crystal at Y1 if it was a mk1 i don't remember vid was to long, bring on the vids of WWF/NBA Jam
 
No problem dude, thanks bunch for your time. I knew I should have checked it when I had the CMOS removed.

The pads on the CMOS are so small compared to other PCBs I've worked on so it was a bitch soldering it down.
 
No problem dude, thanks bunch for your time. I knew I should have checked it when I had the CMOS removed.

The pads on the CMOS are so small compared to other PCBs I've worked on so it was a bitch soldering it down.

I've seen guys install drill through the board and install a socket for the CMOS chip to go in. They bend the curved legs of the surface mounted chip straight and install it in the socket. Not sure how they made sure everything was soldered correctly being that most of the traces are on the component side of the board under the chip/socket, but they made it work.
 
In the name of all that is Holy, do NOT connect the red and blue wires!
 
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