18 Jul
2014
18 Jul
'14
2:22 p.m.
On 2014-07-18 11:39, emanuel stiebler wrote:
If you have a -U CPU board, there is no RAM built into the machine. You
must have a RAM board in an exmapnsion slot, and it must be addressed at
the top of the address space
Giuven that thaere are several edge conenctors involved between the CPU
board and RAM (CPU board to motherboard, motherboard to expansion
backplane, expanssion backplane to RAM board), a lot of RAM problems are
nothing more than bad contacts somewhere. It's worth pull all the boards
and cleaning the edge bingers nad connecotrs.
If that doden't gix it, I'd probably start o nthe RAM board. Is it being
accessed at all? Check the otuput of the address decoer, etc. If not,
maybe a CPU board problem (buffers, etc). Maybe an address decoder
problem on the RAM board.
-tony
BTW, are there any schematics out for the cpu
board?
I guess, I got a bad one. But even the pinout of the
backplane connector would help, to put a scope on it ...
Found them. Just remembered, that Tony made some ;-)
Didn't find them first time I looked.
Now to figure out, why the RAM fails...