19 Feb
2013
19 Feb
'13
3:43 p.m.
Hi all,
Tony, thanks for your input, we will check the PSU on Thursday when we
get to the machine again.
Yes, do. No machine will work properly if the pwoer is all over the
place. And it's a suprisingly common problem with very odd symptoms. In
any case, if you can elimuinate the PSU as the source of the problem,
that/s one less thing to have to work on.
as Christian pointed out, the problem is not so much the pure amount of
components but the puzzle
game of identifying them since they have been relabled.
Ah.... I've worked on enough HP machines to know the problem. Yes, there
are HP equivlent lists, but quite often you find parts not in said lists.
Whats definitely worse when comparing to out old VT100 is that the DEC
manual has one complete definitive
service manual that covers all schemes and logic. For our NOVA i failed
Does it? I've seen 3 differnet video boards in VT100s, and I think I've
only ever sene publisehd scheamtics for 2 of them.
It is not at all uncommon to find the device you are repairing is a
differnt revision elvel from the schematic. And the changes can be quite
major.
to find a comparable thing. I have constantly to go
back an forward through all kinds of docs. Again I may be unable to find
a "real" service manual, if you know any let me know ;)
This is a problem with larger machines, no matter who mede them. Yo
uconfigured them from various moduelks (CPU, memory, I/O , maybe there
were ven cabinet/PSU options) so there's a separate schematic and tech
manual for each section. It makes sense, if the same core memory, say,
was used in many machines, there only needs to be one manual covering it.
But it does mean you're going back and forth between manauls
-tony