[time-nuts] HP 58503B PSU replacement
Dr. David Kirkby
drkirkby at kirkbymicrowave.co.uk
Wed Nov 14 19:39:56 EST 2018
On Wed, 14 Nov 2018, 18:14 Gerhard Hoffmann <dk4xp at arcor.de wrote:
> If more than one replacement unit does not work, then it is not
> improbable that the switcher needs a minimum load to start.
There is a minimum load specified on the 5 V rail, and someone wrote above
that the GPS receiver does not meet that requirement.
I tested my supply in the GPS receiver, but it may be worth having another
go while definitely meeting the load requirements.
> Also, a shorted capacitor can show excellent ESR.
Luckily I have a Peak ESR70 ESR/Capacitance meter.
> I once had a cycling power supply in a W&G TSA-2 spectrum analyzer.
> It delivered power for some seconds, and that was enough to trace
> a voltage to a faulty feedthrough capacitor. A DVM with enough digits
> helps a lot. Towards the short, the voltage sinks mV by mV.
One of the problems with this PSU is a lot of components are glued
together. It is almost impossible to see if some tracks belong to a
capacitor or not.
The board layout leaves a lot to be desired. There are components mounted
about 45 degrees to the board to fit them in.
> regards, Gerhard..
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