Fast ram not being detected in amiga 4000

[amiga4000freak]

hi to all

I have a amiga 4000 rev b and its not detecting my fast ram.
I have played around with jumpers and nothing happens would it be best to use a zorro 2 card with 4meg of ram or do i invest in a zoram from amiga kit instead so it will be using zorro 3 which is faster. Im only using the amiga for games any suggestions would gratefull

[joekster]

I have a couple of a4000 in this state. I'm 99% sure its caused by battery leakage (at least in my case).

[spaceman88]

Hi,
I also had a couple of A4000 boards with no or intermitant fast RAM. I was able to repair them with a toothbrush and some contact cleaner then cleaned it up with some alcohol. There seemed to be a corrosive reaction between the contacts on the RAM and the contacts on RAM slots. It was worse near the battery so I think that was the source of the problem.

[alexh]

It could be the wrong type of SIMM. If you've not used these SIMMs before it could be that you need a different configuration of chips (more or less per SIMM)?

I suspect like the others it is more likely to be motherboard battery alkalie damage.

[amiga4000freak]

hello

yes i have tested two different ram chips an it only detects 2 meg chip ram

[alexh]

Two different as in two different types with different numbers of chips?

[SACC-guy]

wasn't four 72 pin page mode 4 meg simms in all four slots or
two 72 pin fast page mode 8 meg simms in sockets one and three
for the sixteen total

Michael