Backup RAM error 5555 B255 was what I started with, with a dead battery, and a little corrosion on the terminals.
I replaced that battery, and now I get, "WRITE 0000 READ 0055"
I was told to look at channelmaniacs posts, and look to the connections between rams and the CPU in resolving this.
I found this post:
http://www.neo-geo.com/forums/showth...kup-RAM-errors
With info on the pinouts for the chips to the CPU. Those checked good, but the post looks like its for the four-slot, and not the 2 slot that I have. So I'm not sure if that matters.
The rest of the pins - to the 74hC32 chip, 2 were there, and two weren't (the ones to pin 13).
The reference there is to D10, but mine aren't there - the 74 chip is at J2, so I'm not sure if the pinouts are correct.
Does anyone have the correct pinouts for the 2 slot from the SRAMs there? I have been looking for the last hour or so, and all I keep finding is for the one slot, or the above post.
I dont SEE any corroded traces, but they are pretty tiny on this board. I am thinking it might be the 74HC32 chip?
I am also told I can get a univeral bios for around $50 for this board, but I'd hate to pay that and it still have problems. (I have a working board; I want this one as a spare done CHEAP! haha)
Heres the pinout info i used, which I'm not sure is for my board:
"RAM___CPU
1______43
2______41
3______36
4______35
5______34
6______33
7______32
8______31
9______30
10_____29
21_____39
23_____40
24_____38
25_____37
26_____42
etc.
There are 3 pins for each backup ram chip that are not connected to the CPU:
lower ram:
20_____74HC32 (13) located at D10
22_____PRO-C0 (16)
27_____74HC32 (8) located at D10
higher ram:
20_____74HC32 (13) located at D10
22_____PRO-C0 (8)
27_____74HC32 (6) located at D10 "
I replaced that battery, and now I get, "WRITE 0000 READ 0055"
I was told to look at channelmaniacs posts, and look to the connections between rams and the CPU in resolving this.
I found this post:
http://www.neo-geo.com/forums/showth...kup-RAM-errors
With info on the pinouts for the chips to the CPU. Those checked good, but the post looks like its for the four-slot, and not the 2 slot that I have. So I'm not sure if that matters.
The rest of the pins - to the 74hC32 chip, 2 were there, and two weren't (the ones to pin 13).
The reference there is to D10, but mine aren't there - the 74 chip is at J2, so I'm not sure if the pinouts are correct.
Does anyone have the correct pinouts for the 2 slot from the SRAMs there? I have been looking for the last hour or so, and all I keep finding is for the one slot, or the above post.
I dont SEE any corroded traces, but they are pretty tiny on this board. I am thinking it might be the 74HC32 chip?
I am also told I can get a univeral bios for around $50 for this board, but I'd hate to pay that and it still have problems. (I have a working board; I want this one as a spare done CHEAP! haha)
Heres the pinout info i used, which I'm not sure is for my board:
"RAM___CPU
1______43
2______41
3______36
4______35
5______34
6______33
7______32
8______31
9______30
10_____29
21_____39
23_____40
24_____38
25_____37
26_____42
etc.
There are 3 pins for each backup ram chip that are not connected to the CPU:
lower ram:
20_____74HC32 (13) located at D10
22_____PRO-C0 (16)
27_____74HC32 (8) located at D10
higher ram:
20_____74HC32 (13) located at D10
22_____PRO-C0 (8)
27_____74HC32 (6) located at D10 "