Galaga help

shilmover

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I am getting either a "RAM 2L" or "RAM 4H" error on my galaga board.

I have replaced all the 9114 RAM chips, no difference.

Any suggestions?
 
i had a bad ram on a star wars board, replaced it, still had a ram error, replaced the socket, still had the error, metered it and found a bad trace.
 
Check the sockets on the 08xx custom IC's. Also check them for broken off or loose pins.
Make sure those RAM's are 200ns, slower RAMs will cause supurious RAM test failures on Galaga.

- James
 
Check the sockets on the 08xx custom IC's. Also check them for broken off or loose pins.
Make sure those RAM's are 200ns, slower RAMs will cause supurious RAM test failures on Galaga.

- James

The chips are:
AM9114EPC
8432QPP

How can I tell what speed they are?

The 08xx chips look a bit tarnished, but I will reseat them and test.
 
The chips are: AM9114EPC

Datasheet archive has the AM9114, so looking at the suffix codes 'E' = 200ns 'C' = 300ns and 'B' = 450ns

So the AM9114EPC should be fine. Check out the 08's though, it may be worth just swapping their sockets out anyway if they're the classis single wipe Midway style.

- James
 
The 2114's address bus is driven by the 04xx on the video board.
 
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