Easy job: the game soon after POST coined up immediately.
Ran the I/O test and the coin button didn’t work (but it showed a 0 instead of 1).
Testing pin 16 of Jamma connector (coin input) showed that it was stuck low all the time.
Tracing back with the multimeter I found out that the responsible for coin inputs was a 74ls257 TTL @19C which I replaced.
That fixed the problem.
Game booted and could be played but all the screen was full of garbage and flashing.
I found one of the two rams circled in red that was really hot. Data signals were weak so I decided the replace it.
I could now see some parts of the background, so I decided to replace also the other ram and the game this time was fully restored.
After receiving news that Eduardo Cruz had updated the code of the Kabuki Desuicider to support also the final games with eeproms that in the past didn’t work (Super Pang and Poker Ladies), I took my Poker Ladies board to desuicide it.
After reprogramming the Kabuki chip
I fired up the game but I was welcomed with a bad surprise:
I had corrupted graphic on some sprites ( title sprite and back side of the cards).
Luckily after locating the 2 chips responsible for the sprites, one of them ( @2J )had internal damage (programmer warned about missing contact on a data line)
The chip was a 1mbit maskrom but 32pin, that means I could do a 1 to 1 change with a programmed 27c1000 or equivalent without any flying wires.
Problem was 100% fixed
After 6-7 years years I decided to dig up my Centipede board (already repaired several times in the beginning) to make a play and I noticed that it was too quite.
Some sounds were present but something was missing…
After firing up Mame I immediately noticed that the sound missing was the centpede one!
After a brief looking at the schematic I understood that the Pokey chip was somewhat faulty.
Started the tone test and the channel 4 was silent.
Luckily I had a Missile Command lying around which was in very bad conditions but the Pokey was good!
So sound fully restored changing the Pokey chip @C3
After fixing a couple of Pac Man PCB’s recently, the owner of them very kindly let me keep one of the boards. The only problem was it had been stripped of the ROM’s and customs.
Now the customs are no longer a problem for me but the ROM’s are of the 2532 variety and I only have a couple of them free.
As luck would have it user ‘philmurr’ on the UKVAC forums has made a nice little drop in replacement that fits in the Z80 socket and lets you use a single 27c128 EPROM in place of the 4 x 2532 program ROM’s.
I got it today, assembled and fitted it without issues.
Game plays as you would expect.
A couple of caveats. There are a few wire link mods needed to the PCB due to an error but these are well documented in the instructional PDF and the boards are so nicely priced that it really doesn’t matter too much, at least not to me.
The other potential issue is that if your PCB is fitted with the TTL custom replacements then this board just isn’t going to work for you as the custom covers the original Z80 socket.
Really happy with this so thanks to Phil.