> From: Lou
>
> I had a similar problem and it had me stuck for months. I
> finally located a bad 3 pin RAM selection jumper switch on
> the board. It had become slightly corroded. Once replaced
> with a nice new gold one (including jumper), things started
> working properly. My bad for not checking it earlier. Anyway
> it’s easy to rule it out and maybe worth checking.

It's a good idea, in an old Polaris that isn't running, to reseat every connector, including partially lifting and reinserting every socketed chip. There are a number of jumpers, including a 4x4 block of pins that routes interrupts and DMA requests. Sliding each jumper off and on a couple of times is a good idea. I've not seen any that were fatally corroded, but I suppost that can happen if there was enough moisture.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...