looking for a working 11/05 (KD11-B) board setu
ard at p850ug1.demon.co.uk
Sun Jun 13 12:24:26 CDT 2010
> Tony has a good point here: it's usually the support stuff (power supplies,=
> connectors) that bugger up a machine of this simplicity. -- Ian=20
Even if it isnt, I fail to see what good a spare CPU board set will do.
I know I am in aminority here, but I truely believe the only way to put
something right is to find the fault, and then to correct that fualt. Not
to randomly swap parts until the machine _appears_ to work again.
In any case, I don't know anyone who would be prepared to risk any PCB in
a machine where the health of the PSU isn't known.
The first thing to do is to discover just what it is and isn't doing. If
it were my machine I would start by checking the PSU with a meter and
'scope. PSU problems can make you think there's something wrong with just
about any part of the machine.
Then I would try reading and writing memory. If that fails. I'd stick in
a DL11 or something and try reading and writing that (if that works, it's
_likely_ there's a problem in the memroy section). And look at the Unibus
lines when doing meoroy accesses from the panel -- do they look right? If
not, there probably is a problem in the CPU -- then it's time to see
which signal(s) are wrong, what drives them, could there be a common
cause, check 'earlier' signals in the CPU logic, and so on.
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