VAXstation/MicroVAX 2000 CPU/FPU overheating?
ard at p850ug1.demon.co.uk
Thu Feb 28 13:32:32 CST 2008
> > > A good idea, but I don't think this is the case. According to the technical
> > OK... Not having seen the machine, all the rest of us can do is make
> > guesses, most of which are likely to be wrong :-)
> If my response came across as critical, I apologize, this was not my intent.
> I welcome any and all suggestions.
No, not at all. Hence the smiley.
> > > I'll have to do some measurements. I could try hard-wiring the fan to full
> > > power, however this thing *should* work as it is designed, and the fan supply
> > True. On the other hand, if making the fan run at maximum speed all the
> > time keeps the machine running, it's worth doing that mod (IMHO) to save
> > the problem of replacing the CPU or FPU chips.
> Agreed that it wouldn't hurt to have the fan at full power, but the point I
> was trying to make is that this thing gets *SO* hot that I'm convinced theres
> a fault, which should be found, not masked.
I assume these CPU and FPU chips are MOS devices. Is it possile that
excessive leakage across the gate oxide layer in some transsitors of that
chip would cause it to run hot, but still work? I'm pretty sure I've seen
chips that seem to work, but get hot and then stop working, althoguh
cooling them with freezer spray keeps them running. And these were not
chips driving high pwoer laods -- they were things like the clock/timer
microcontroller in a VCR.
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