I fried a Namco system 1 board

[Kenth333]

Hoping to get some help with a board I f* up. I had the jamma connector on backwards (oops

) and am now getting a RAM4 error. It's a Namco system 1 board so I've been looking through a Pacmania schematic and manual and came up with the following:

Can anybody tell me if I'm on the right track and where I would be able to get replacement parts for H1 and H2 (is this ram??)? The connectors I hooked the voltages up to only lead to those two components and I'm hoping it burnt out there.

schematics: https://archive.org/download/pac-maniasp-3151stprintingschematicpackage/Pac-Mania-SP-3151stPrinting-SchematicPackage.pdf

 

[Kenth333]

Spent a few hours last night trying to find out what that is and where to get it, but I just now found it's a namco custom input SIL (?). I found some that have the 95 JAPAN marking on them but they didn't have the number 75. Would I still be able to use them on this?

 

[simonden]

I believe that you are on the wrong track.

I don't have a board but according to the manual, there are 2 boards, is that correct? The H1 it is referring to is H1 on the other board which is either a standard 6264 RAM chip or a 2018. Both of which are very easy to get. The IC that you are playing with is a Namco Custom 95!

Go back to the manual (the one that says it is RAM at location H1) and look at the board layout in there. Section 4-16 which is the board with the RAM error and section 4-19 which is the board layout for the one that you are looking at.
simonden2013-11-21 13:08:39

 

[Kenth333]

Thank you!
I just assumed it was the rom pcb because the component marked H1 was the first component traced from the jamma connector. Wouldn't it have blown components on that board before ever getting to the cpu board? Sorry if a dumb question.

 

[simonden]

Wouldn't it have blown components on that board before ever getting to the cpu board?

Possibly, but at least check/fix the parts that it is telling you about before trying to guess whether anything else may be broken.

 

[Kenth333]

I was troubleshooting a sound problem when i managed this so something else will be broken, but now I'll be happy if I even get it playing again. Live and learn.
Kenth3332013-11-21 13:40:32

 

[andrew96]

Jamma connector on backwards usually sends 12v up a couple of the switch inputs, now I don't know your board but on ones I have seen switch inputs are buffered by something like a 74ls245 AND if the blow goes through them it can hold bits high on the data bus and could give the errors you are seeing. so my advice would be to check carefully where the 12v line would have gone!! I now disconnect the 12v on my test rig until i have the board running well THEN apply the 12v, cause yep I one the same too!!
andrew962013-11-21 13:49:51