Super Wild Card RAM upgrade (SNES Copier)

I opened this up initially just to remove the battery before it leaked but noticed two empty spaces for more ram which would take it from 24mb to 32mb. Would it be a case of simply soldering in two more dram chips?

There isn't much information out there but a google search did find some forum threads that suggested I'd have to replace or reprogram the two PAL/GAL/PEEL chips (PEEL in my case) and also cut some traces / add some wires so the machine could make use of the extra memory.

The ram looked familiar, I checked some old pc ram I have and sure enough one stick (dated 1992) with the exact ram chips on it, even the same manufacture perfect!.

 Added some chip quik to two of the chips and yoink.

Two rams added to the SWC and two decoupling caps (one on the underside of the pcb).

Time to power it up and make sure it still works.

It works and how much ram does it see..

Woot! I need to do some more testing but it looks like the upgrade was a success.

UPDATE: Looks like I need to replace the PEELS and do the wire mods as loading any 32mb rom results in a black screen, to be continued.

Elevator Action PCB Repair (from hell)

This pcb was bought from ebay years ago as untested when it arrived and I saw the state it was in it was stored away and been stored ever since. More recently I got a working Elevator Action pcb in a job lot of boards which reminded me about this one and having a working one could help narrow down which were the faulty layers by swapping on to the known working board.

Out of the five layers only the second one (sound board) worked correctly, even the tiny rom board on top was dead.

I didn't do a good job of documenting this repair as it was spread out over a week or so while waiting for parts and between doing other jobs. From the list of parts I had to replace you can see it was a bad one though, if I had known how many parts were bad and how long it would take to get running it would still be in storage or maybe the scrap pile. :)

 This is most of the bad chips, I forgot to save the 40193s.

The board had obviously had a nasty power spike or been hooked up incorrectly at some point as it wasn't just fujitsu ttls (although there were quite a few of those too). The ribbon cable that joins the security mcu board was even melted and had to be replaced.

I managed to reuse one of the original 40 way idc connectors but the other split so I had to replace it with a new 3M one. The originals are much nicer quality than the 3M but it does the job.

Here's a complete write up of every part replaced for those interested.

Top PCB (Small rom pcb)

3x CD40193 4bit counters which I had to order. UC10,11,13

Layer 3

2114 RAM - IC17,18

74LS157 - IC1,13,14,76

74LS86 - IC28,42,70

74LS374 - IC24,34,99

74LS10 - IC54

74LS74 - IC7

Layer 4

74LS138 - IC76

74LS157 - IC77

74LS32 - IC94

74LS74 - IC87,89,90,97

74LS374 - IC8

6116 RAM

Layer 5 (Security MCU / CPU board)

74LS245 - IC19

Ribbon cable

Repair complete.