dbstallman
Member
I picked up a dead Aliens Vs. Predator last week expecting a quick and easy fix to add this excellent CPS-2 game to my collection.
Unfortunately, when I opened it up, I was greeted with this :
Here is a closeup of the damage :
This battery didn't simply commit suicide, it blew it's brains out with a shotgun! My heart sank. I could easily transplant the ROMs to another board and be done with it, but instead I decided to take up the challenge and attempt to bring this one back from the dead.
I removed the battery and started to clean off the largest chunks of oxidation and battery residue. I was hopeful that at least some of the damage would be just superficial and I could quickly get the board back in business.
After I had the bulk cleaned away, I burned Raz's Suicide Tester ROM and put it on the board just check and see how bad the damage was. It booted up and passed all the tests with only a slight amount of graphical glitches in the text. This was very encouraging.
I started trying to get all the battery residue off the board. The electrolytic cap in front of the battery and a small transistor that is between it and the battery popped off with the residue, but both of those components are part of the suicide circuit and not neccessary for the Phoneix code. I was able to successfully clean completely around the two 74LS245's, but I noticed the one closest to the battery didn't appear to have any connection to the board now. With only a small amount of further cleaning, it popped off the board. I tried to get the residue out from between the legs of the other 74LS245, but it soon came off the board as well.
All components within the toxic spill were now off the board and I was able to remove all the battery residue and oxidation. The board was now clean and I needed to start working to get it back into operation (sorry, I neglected to take a picture at this stage). I retested the board with Raz's ROM and got a blue screen but could hear the music playing. I went ahead and replaced the game ROMs with new Phoneix code ROMs and gave it another test. The screen was still blue, but I could hear the attract mode running and it responed to coins and played blind (well, blue).
I was able to find two 74LS245 SMD chips on a CPS-2 "A" board with bad cartridge connectors. I replaced the one that was farthest from the battery first since it still had the majority of it's solder pads in place with 15 of the 20 pin connections still functional. The last 5 connections I was able to jumper with short piecees of uncoated wrapping wire.
The other 245 was the tricky one. With no solder pads left for it, I needed to determine where the traces were supposed to go. I pulled another of my CPS-2 "B" boards and started following the traces. The pins on the side closest to the battery travelled under the chip and through vias to the bottom of the board. From there they went almost to the program ROMs and then through vias again back to the top. That looked like the best place to get my signal from. The pins on the opposite side of the chip just connected directly to the cartridge connector right below it.
I wired the chip up:
and then gave it a test:
Success!
This is my first repair log (although not my first repair). I want to give something back to the community since I have learned so much from the repair logs of others (ifkz, womble, channelmaniac, etc.). I hope this helps someone or at the very least is an interesting read.
Thanks,
Brian.
Unfortunately, when I opened it up, I was greeted with this :
Here is a closeup of the damage :
This battery didn't simply commit suicide, it blew it's brains out with a shotgun! My heart sank. I could easily transplant the ROMs to another board and be done with it, but instead I decided to take up the challenge and attempt to bring this one back from the dead.
I removed the battery and started to clean off the largest chunks of oxidation and battery residue. I was hopeful that at least some of the damage would be just superficial and I could quickly get the board back in business.
After I had the bulk cleaned away, I burned Raz's Suicide Tester ROM and put it on the board just check and see how bad the damage was. It booted up and passed all the tests with only a slight amount of graphical glitches in the text. This was very encouraging.
I started trying to get all the battery residue off the board. The electrolytic cap in front of the battery and a small transistor that is between it and the battery popped off with the residue, but both of those components are part of the suicide circuit and not neccessary for the Phoneix code. I was able to successfully clean completely around the two 74LS245's, but I noticed the one closest to the battery didn't appear to have any connection to the board now. With only a small amount of further cleaning, it popped off the board. I tried to get the residue out from between the legs of the other 74LS245, but it soon came off the board as well.
All components within the toxic spill were now off the board and I was able to remove all the battery residue and oxidation. The board was now clean and I needed to start working to get it back into operation (sorry, I neglected to take a picture at this stage). I retested the board with Raz's ROM and got a blue screen but could hear the music playing. I went ahead and replaced the game ROMs with new Phoneix code ROMs and gave it another test. The screen was still blue, but I could hear the attract mode running and it responed to coins and played blind (well, blue).
I was able to find two 74LS245 SMD chips on a CPS-2 "A" board with bad cartridge connectors. I replaced the one that was farthest from the battery first since it still had the majority of it's solder pads in place with 15 of the 20 pin connections still functional. The last 5 connections I was able to jumper with short piecees of uncoated wrapping wire.
The other 245 was the tricky one. With no solder pads left for it, I needed to determine where the traces were supposed to go. I pulled another of my CPS-2 "B" boards and started following the traces. The pins on the side closest to the battery travelled under the chip and through vias to the bottom of the board. From there they went almost to the program ROMs and then through vias again back to the top. That looked like the best place to get my signal from. The pins on the opposite side of the chip just connected directly to the cartridge connector right below it.
I wired the chip up:
and then gave it a test:
Success!
This is my first repair log (although not my first repair). I want to give something back to the community since I have learned so much from the repair logs of others (ifkz, womble, channelmaniac, etc.). I hope this helps someone or at the very least is an interesting read.
Thanks,
Brian.



