Seems to have worked out very well replacing the SI board with the used one - luckily the battery voltage seemed fine so didn't need to switch the batteries on the replacement board either. Cluster is now working fine.

Figured I'd take a gamble with buying a used cluster (reported to be in full working order) and see whether I can salvage the SI board from it. Will report back on how it goes.

Thanks - will give it a try

I'm not really sure what has happened to it. Batteries hadn't leaked. The rev counter has been pretty much useless since I got the car. I tried another cluster, which worked fine. Then borrowed the SI board out of the working cluster ad put it in the original cluster - worked fine. Changed the batte...

Hi all - wondering if anyone here has a recommendation for where I could get a replacement/rebuilt SI board that will work in an E30 M3, or were I could get mine repaired, please?

Thanks,
Charlie