[Test-Equipment] Sprague TO-6A question

[k4pf at juno.com]

Hi, Ken

Yes, the metalized polyester caps will do fine as the standard caps.
I assume you'll select some with your digital cap meter 
for the required accuracy.

A good test for the insulation resistance metering function 
of the Sprague is to connect a 20K Ohm/Volt VOM set to 1KV dc 
across the terminals.  That represents an accurate 20 Megs. 
Two such VOMs in series, each set to 1KV dc would be 40 Megs.
If you have a high voltage probe to add, all the better.
I have a 40KV probe for a Simpson 269 VOM, 100K Ohms/volt,
so the combination is 4000 Meg Ohms.

One thing you should watch is that the pot used to set the insulation
resistance meter to full scale should not be set too far.  
You just want the meter at the "set" point with nothing connected
to the terminals, not have the meter pegged at full scale.

73,
Ed Knobloch


 "Ken Kaplan" <krkaplan at cox.net> wrote
>> Yes, I checked the old C16. It measures 50K which I think means 50K
>> megohms or 50 gigohms. Seems like enough but I guess not for the
>> circuit. The new replacement indicates infinity. 
>> I know the other tests are not of much value but I wanted 
>> to gather as much info as I could. 
>> My new replacements are Mallory metalized polyester. 
>> You think polyethylene film would be better?