Donkey Kong 3 monitor showing gibberish

[Lutus]

I'm not sure if this is the best forum to post this in but in the past it has been the most helpful.

I recently purchased this DK3 machine and restored it to a DK original.  This can be seen here http://forum.arcadecontrols.com/index.php?topic=57623.0

On one of the pictures in that topic, (and attached below) you will see what the monitor is showing on bootup.

Little history.  Mike's Arcade has shopped this board in the past.  The seller said when he received it back it showed on the screen as seen in the picture.  He emailed Mike's arcade and Mike said that it could be the power supply.

I, just yesterday, checked the power supply output and replaced some shady looking resistors on the PCB.  I still receive the same output on the monitor.  Gibberish.

Where should I focus my attention?

[cw]

was the voltage low?

[Lutus]

No, did not appear to be.  I will recheck but no it wasn't low.

5 volts showed as 5.12 or something like that.  Each was very close.

[grantspain]

looks like eprom/graphic ram/general i.c failure or interboard connection problem to me

[Lutus]

One of the chips looks like the heatsink has come off of it and looks generally "shady".  I guess is the word.

[cw]

I did a little digging and found this note on mikes arcade



Problem: game plays but numbers instead of graphics fill the screen

Solution: replace bad 2114 RAM at 2P on the video board.

its listed as a fix for a dk junior but it might be the same pcb set.. still looking

[Lutus]

This guy used Mame and recreated a bad chip for all the chips on his DK board set.  Then he compared the image to see what chip was wrong.  Very interesting read and do you think this would be possible for DK3?

http://www.brasington.org/arcade/tech/dk/

[Lutus]

Over a year later and I am back.  I won a DK3 board off of ebay and placed it in the machine last night and it works!!!

I then performed capkit surgery that I have been meaning to perform since... well, OCT 2006.  My new job has kept my schedule slammed.... but how many people get business travel to Hawaii for 3 weeks?   

I will be troubleshooting the first board again, so will update again once that process is started.