[R-390] Re: Collins R-390A restoration

[Drew Papanek]

Brian McCagherty wrote:


>To test the caps I have a choice of:
>a) Heathkit C-3U R-C Bridge with 450V leakage test (EM34 Magic Eye
>indicator), or
>b) Solartron stabilized variable PSU at 450V DC max through (say) 50K and
>metered externally on an Avo.
>I also have a cranked Megger at 625/1250/2500 V but this is rough a.c. so
>not suitable for capacitors I reckon.
>However I don't have anything I would recognise as a "high resistance
>meter"; is (b) above the same thing?

The Solartron power supply can be used along with a high impedance voltmeter 
(DVM suitable) as a very sensitive capacitor leakage checker.  Set the power 
supply to the desired test voltage. With due respect for the high voltage, 
connect the power supply, meter, and capacitor under test all in series.  
The leakage current is found by dividing the meter reading by the meter's 
input impedance.

You can find out much more on the topic of capacitors (and all other topics) 
pertaining to the R-390 series at r-390a.net

In particular, check out "Pearls of Wisdom" on the the "references" page.

Drew

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