If you're using the original swinging choke input supply, remember that you cannot "test" it unless you have it connected to the amp or you add additional bleeder..
I wouldn't use the amp(for testing)? until I know for sure everything is ok in the PSU.?
An easy way to do it is to temporary install additional bleeder resistor(s) in the power supply to approximate the reduced idling plate current of around 45-50mA
If your power supply is original, it should do somewhere around 3000v.? The original bleeder is 210k
I=V/R ? or 3000/210000 = approx 14.3mA?
So you need around 45mA or so additional draw on the power supply to get the swinging choke swinging!? (Halliscratch did it with the final tube in the amp when the "jumper" on the back of the RF deck was in place)?
The additional resistor needs to be in parallel with the 210K
?For 45mA.......R=V/I or 3000/0.045 or roughly 67K?
AND since it's going to get pretty hot, it needs to dissipate some serious power.? P=Vsqr /R? Or 3000 * 3000 /67000 = 134W
Or if you prefer I(squared) * R ?? (0.45)SQR x 67K
Since you're not leaving it powered for long periods of time, you can use lower power resistors for short periods of voltage measurement.? You could even use? 50K resistor but the current will be higher and it's important to use 67K because this approximates the 40-50mA the tube will draw in standby
USE? A HIGH VOLTAGE PROBE, I got this one:
BK PR 28A 40kV High Voltage DMM Probe
I think I gave about $40 for mine.? I know they're more expensive now.? But don't skimp on something that could end your life!!
Hook everything up and stand back! then throw the switch.? (keep one hand in your pocket!!!)
If you try to test it with the amp and the (idling) current draw is low (below that which would make the choke work properly)? for some reason, the plate voltage could likely exceed 4000V and destroy the meter, oil capacitor and other components in the amp...... so it's imperative that the power supply is "right" before you hook up the RF deck
--
73/Rick
W4XA
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Rick W7IMM