Donkey Kong Jr (Good working order)

I just picked up this Donkey Kong Jr board from ebay, described as good working order. It certainly wasn't by the time it made it to my door step, it didn't help that it wasn't even put in a box. Bubble wrap and brown paper... typical ebay.

I didn't bid much on this as I thought there was a good chance it probably didn't work given that his Nemesis board was listed as untested / unable to test.

I did think it was an orignal Nintendo board though as it looked the same as an original from the low res pictures and I didn't know bootleggers did 1:1 copy boards. Turns out they did, all they changed was adding an audio amplifier and out putting standard video instead of inverted. This is better in some ways but it also means I cannot use my Mike's Arcade Nintendo to Jamma adapter.

First thing I had to do was wire up an adapter.

I've had to made a lot of these over the years and it never gets any less tedious.

Before hooking it up I had a good look over the board, I noticed a pad was missing on the edge connector, looking at the pinout this is Green. So it is going to need to be sorted, I lifted a pad off of a scrap board and glued it down then ran a small piece of kynar wire. 

It's not winning any beauty contests but it'll work.

I power it up and got no sync, this is a common problem on original board too. I knew this already from a previous repair, the pots on the bottom board get damaged and the board won't sync. This can happen when you post it without putting it in a box first!.

Resoldered the two legs that had lifted on the vertical pot.

 Things aren't looking good

or working.

Now I decided to reseat all the EPROMS and check them with romident while I was at it.

EPROMs 7E and 7F both had data romident didn't recognize.

These EPROMS didn't look original to the board, looks like they were just thrown in to complete it. Testing again sorting these two roms didn't help much.

After looking at the 2114 rams everything looked ok so I decided to go Fujitsu spotting. These two 74LS74s on the top board were the first two I looked at.

I stuck the HP Comparator on the top chip (7F) as it was right next to me and even had the 7474 card in it.

It lit up like a christmas tree.

I removed and replaced both 7474s as they were together and both Fujitsu but only 7F was bad.

It looks like MacGyver has worked on this board at some point, what do you do when you lose the pcb spacers?

 Melt a bic pen and hold the pieces in place with wire of course.

Replaced with some cheap spacers from China.

 There was also this strange ram bodge.

He looks so lonely.

 Game is now in good working order.