Subject: RE: DEC 3000/M400 cooling
To: 'der Mouse' <mouse@Rodents.Montreal.QC.CA>
From: Schwerzmann, Stephan <email@example.com>
Date: 07/29/2004 09:15:07
>> my thoughts go the following path: possible little spare margin of
>> cooling power by original design -> aging -> [...
>This could be. It hasn't been sitting idle for all that long, only a few
months, but you never know.
it's not the time sitting idle, but the 'warm...hot life' before that
has the relevant impact on aging - shelf life (="time sitting idle") of
electronic components is close to excellent
it's different for mechanical components such as bearings found in blower
by not being use they tend to become "sticky" -> less RPM -> less airflow
-> less cooling power (I _beleive_ "goo'ool" DEC workstation & server
equipment was designed taking care of these facts...)
>> you also mention hot circuits near the connectors to the outside
>> world, right? may it be that the venerable machine suffered an a tad
>> to strong dircharge (think surge, ESD or the like) ?
>I suppose it could have been, but I doubt it. Some of the reasons:
>- The machine wasn't connected while it was sitting idle.
>- The external-interface electronics still work.
>- The heat is coming not from the daughterboard, where the interface
> electronics that would take a hit are, but from the motherboard just
> below it.
>- The two places that are running disturbingly hot are both populated
> by the same kind of chips (small square surface-mount packages of
> some 20 to 30 pins each).
>The power supply idea is a good point; I should find an accurate voltmeter
and measure the supply rails.
the "accurate voltmeter" you are looking for is a scope! (oscilloscope)
when DC power is/gets noisy/spiky/ripply this does not necessary mean
that the average voltage (the value all DC voltmeter show you) goes "out