Had to share with a group that would understand:
Been working on four Asteroids boards for what seems like months... learning as I went along and slowly improving the boards, acquiring test equipment, and finally getting one of the boards completely fixed. Then the second, then the third and fourth! Confidence cautiously building but another part of me thinking "wow this takes a long time."
Then yesterday with all the Asteroids boards fixed, I decided to do other B/W vectors since I had the power brick and monitor at the bench. Pulled two Battlezone boards I've had forever and an Omega Race with some battery damage. Found a bad RAM and LS245 on the BZ by piggybacking good chips on the bad ones... cut out the two bad chips and socketed new ones, game plays but no background objects. Tracked it down to one more bad chip that stores the brightness levels - one of the three Z level pins was not pulsing - replaced the LS175 and it was fixed. Reflowed the solder on the interconnect header and replaced one of the VROMs self-test said was bad and that fixed the second one.
Feeling very good, I moved on to Omega Race and was getting constant resets. Bit the bullet and cut out the two chips nearest the battery (the LS245 disintegrated as I did) and pulled apart two RAM sockets that were green on the inside. Washed the corner of the board, installed new sockets and fixed two traces and got... the same thing. No self-test even. So I pulled all the socketed RAM and ran self-test and got beeps! Testing the RAM in my MOD-EMUP-A pointed out two bad ones from the group of three in row 2. Replaced those and reinstalled the rest and it's alive!
Three boards I had kind of been dreading but really wanting fixed in one day! Woot! As long as this post doesn't jinx me, I'll be working on Gravitar next. Then maybe the matrix error on my SW/ESB can be conquered.
Been working on four Asteroids boards for what seems like months... learning as I went along and slowly improving the boards, acquiring test equipment, and finally getting one of the boards completely fixed. Then the second, then the third and fourth! Confidence cautiously building but another part of me thinking "wow this takes a long time."
Then yesterday with all the Asteroids boards fixed, I decided to do other B/W vectors since I had the power brick and monitor at the bench. Pulled two Battlezone boards I've had forever and an Omega Race with some battery damage. Found a bad RAM and LS245 on the BZ by piggybacking good chips on the bad ones... cut out the two bad chips and socketed new ones, game plays but no background objects. Tracked it down to one more bad chip that stores the brightness levels - one of the three Z level pins was not pulsing - replaced the LS175 and it was fixed. Reflowed the solder on the interconnect header and replaced one of the VROMs self-test said was bad and that fixed the second one.
Feeling very good, I moved on to Omega Race and was getting constant resets. Bit the bullet and cut out the two chips nearest the battery (the LS245 disintegrated as I did) and pulled apart two RAM sockets that were green on the inside. Washed the corner of the board, installed new sockets and fixed two traces and got... the same thing. No self-test even. So I pulled all the socketed RAM and ran self-test and got beeps! Testing the RAM in my MOD-EMUP-A pointed out two bad ones from the group of three in row 2. Replaced those and reinstalled the rest and it's alive!
Three boards I had kind of been dreading but really wanting fixed in one day! Woot! As long as this post doesn't jinx me, I'll be working on Gravitar next. Then maybe the matrix error on my SW/ESB can be conquered.



