DEC Rainbow PC100-A

shadoooo shadoooo at
Sat Jan 16 15:15:55 CST 2016

I recently took a DEC Rainbow PC100-A.
It has been a huge house for a lot of spiders, who deposited eggs and 
dead insects all around.
After full disassembling, cleaning and reassembling, I'm ready to try it!
PSU seems to work well, power goes on with almost precise voltages, then 
all the test leds on the back will lit on...
then nothing happens! No video, no sign of life.
Clearly there's a problem at the very beginning of the boot phase, that 
could be caused by a lot of reasons.
In the next days I will try to analyze possible causes of the problem 
with oscilloscope,
in the meantime I'm searching a schematic, as board is very complex to 
follow trace-by-trace.

On bitsavers I found a schematic of PC100B, but the main board is not 
the same as PC100A.
Anybody has a schematic for PC100A?

I suspect that ROMs could be damaged, anybody has a correct dump to 
verify the content of the EPROMS?


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