19 Apr
2006
19 Apr
'06
3:01 p.m.
Joe wrote...
I will agree that the HP mechancial construction from that period is
second-to-none, and that the electronic design is darn good too
Now, I have no experience of the HP1000 systems (I would like to fiddle
with one, but they are not common over here :-(), but I have some
experience of the desktop calculators. HP went through a period of not
putting crowbars in their PSUs. The HP98x0 machines had crowbars on just
about every PSU output, the 9815, 9825 and 9831 have no crowbars at all.
For the latter machines, if the chopper transistor in the PSU fails, the
5V line leaps to 30V and takes out just about every chip in the machine,
including the custom CPU module.
Yes I am paranoid about this. I check the PSUs in my 98x5s on dummy load
before turning them on even if they just been sitting on the shelf here.
I ought to add a crowbar, but would I trust it to protect the rest of the
mahcine?
Do you know if the HP1000 supplies have crowbar protection?
-tony
I just check it over and then power it up if I
don't see any obvious
problems. However Tony D advocates removing all the cards, building a
dummy
load and testing the power supply under load. I, for one, am not that
paranoid. YMMV.
HP's truly are built like tanks (speaking of the 2100A/S and
21MX M/E/F
line) - both electronically and mechanically. I don't worry about powering
them up as much as other brands of boxes. One caution - see my previous