System error

[Nepa Coin Op]

I have a few s2000 502/504 boards here all come up with system error
Some of them have zero acid damage
One of them I tried everything
Clear,swap ram positions, change ram chips, change all socketed chips from known good board
Still get the error
Does anyone know where this error originates from to fix it ??
I have full capability to do Smd work here so if a chip is suspect I can change it I just don’t know where to start


Also have another one here that shows an "8" in the credit display and gives RAM ERROR, cant get around it no matter what I try


Thanks




Original chip combo was SB100009 363s vs011nx5, would not boot
I eventually got one board up and running with this combo which from the psr sheet dont seem correct but it works sb100009 362s vs009nx0

[Ash100]

I've seen the "System Error" message come from a bad Sound SIMM or Multimedia Lite Board.


Also pops up if the Version Chip is in the wrong Socket or in Backwards. (Speaking from experience, Lol)


RAM Error will usually clear with a turn of the key etc. I have seen bad RAM though and cleared the errors by swapping it with new ones.


Just my thoughts, good luck.


Curtis ash100

[Stayouttadabunker]

Start with taking out the MML sound board and see if you still get the error.


If not , then you know the MML board is suspect.


No game needs it, it's just a sound option.


Make sure you have a good set of known-working software combo that works on a known-good MPU first.


Sometimes "System Error" is chips in backwards, or bent MPU pins touching each other...take your time...never rush....this is a hobby.

[Nepa Coin Op]

This ones didn’t like the version chip but it’s up n running now.

[Ash100]

Awesome!

[Stayouttadabunker]

This ones didn’t like the version chip but it’s up n running now.

Good job Mike!