[time-nuts] HP 5328 PSU nightmare... Or stupid engineer, you decide...

[Neville Michie]

Hi,
I use a Variac routinely to turn on instruments that have been unused  
for more than a few months.
Electrolytic capacitors will often come good if slowly brought up to  
voltage.
Recently I resurrected a WW2 "Command" receiver that had been stored  
for 40 years.
I hooked up a power supply and set it to 10% of line voltage and  
increased it 10% at hourly intervals.
Slowly warming up the device gives the electrolytics to form up, even  
the paper capacitors get a
chance to warm and dry out a bit.
For fault finding, starting at zero volts you can watch the  
rectifiers start to take up the load, the
voltage regulators cut in when the supply reaches the regulation  
voltage and generally locate
any overloads before the smoke gets out.
The main problem is with switching regulators that abruptly cut in at  
some voltage,
a series tungsten filament lamp helps with them to avoid smoke release.
It always pays to turn it on slowly.

cheers,
Neville Michie


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