21 Nov
2006
21 Nov
'06
10:43 p.m.
Hi Tony
Yes, there is activity in the address lines at least.
I would beleive is gets hung on something. I can see
some activity for a breif period in different parts
of the board. like it was in self test. Then it looks
like it gets hung. Not sure what type of a Processor
it uses, but watching the address lines on the roms
it starts out Ok. With all of the Error codes in the
manual and none being displayed, It would have to be
a very low level problem.
As Dave pointed out, it's not a true DEC item.
So with out much to go off of it would be a long up
hill battle.
- Jerry
-------------- Original message ----------------------
From: ard at p850ug1.demon.co.uk (Tony Duell)
It turns on
and when you push "logic on" it goes
into self test and just stays there with out any
codes displayed. Display just stays at "00"
voltages look close. DEC manual says system main
board or voltages off. I guess they just had a
stack of spare boards to test with.
Again, I've never worked on one of these, so this is very generic
information.
If there's a recognisable microprocessor on the controller board, I'd
check it was getting a clock signal, that the reset line wasn't being
held asserted, and then check that there was activity on the bus lines
from said microprocessor.
This might give you an idea of where to start looking for the fault.
-tony