27 Jan
2001
27 Jan
'01
9:34 p.m.
At 08:13 PM 1/27/01 +0000, you wrote:
I have a resistor like that that I found in a HP PC clone expansion
chassis. I don't know the values off hand but I can dig it out and find
out. I saved the resistor to use as a dummy load for testing power supplies.
Joe
Tony Duell wrote:
[snip]
I don't doubt it existed. It's shown in the Hardware Maintenance and
Service manuals (if you're wondering why I have those board-swapper
guides, it's because I was given them when I bought a second-hand set of
TechRefs...).
What I have never managed to find out (and if anyone here knows, please
let us all know) is (a) what power line this resistor loads (it has to be
either +5V or +12V as it connects to a drive power connector) and (b)
what is the resistance (and wattage) of this resistor. I believe the original IBM PC/AT had a resistor
unit that was screwed to
the chassis and connected to a drive power cable if there wasn't a hard
disk installed. I think it was a load on the 12V power line, which was
otherwise too lightly loaded (no hard disk spindle motor) to behave
properly. I've never seen this device, and it's not shown in the techref
(only in the HMS manual), so I can't be sure.
It decidedly existed. The first AT I owned arrived sans hard disk; when I