On Wed, 24 Feb 2016 17:51:21 -0600, Jon Elson wrote:

Lots of stuff in commercial gear runs at 70 C or even hotter. I don't
like to see parts running that hot. Especially in something that might
get buried in a shield housing deep in the bowels of some piece of gear
like a scope.

I couldn't agree more. Coming from the germanium semiconductor generation
where even slightly too much heat was terminal, I still like to go by the
rule of burnt thumb: if if it burns your thumb it's too hot. In which
case derate, derate, derate.

So, does the scope actually run correctly?

I didn't get the chance to find out! Began this morning trying to get
some voltage readings off the psu outputs and there was nothing there to
read. To cut a long story short, further investigation reveals something
has gone short-circuit on one of the signal boards. When the psu is
removed and run from my make-shift dummy load, it's still 'fine' with its
new diode (not quite right, but functioning to high degree). So clearly I
jumped the gun slotting it back in the scope when it still wasn't 100%
and now it's damaged something - typical!
I'm running out of time now as we have to leave later to spend a few days
with 'er mother 300 miles away and whilst I shall still have internet
access there, I'm not allowed to take any test gear with me. Ain't life
great?