Hello,
as I had initially planned my objective was to exchange all and every "suspicious" capacitor and these selenium rectifiers. Right now I have got a basically well operational instrument, but not yet calibrated as I am still looking for other suspects.
My findings (results read from a Chinese component checker):
1. Bumble Bees: all 10 - 35% off nominal value, VLoss 1.0 - 2.8%
2. High Voltage capacitors (1kV, 3kV, ...): VLoss 1.5 - 2.0%
3. Good-All capacitors: 5 - 12% off nominal value, VLoss < 1%
4. Black Sprague capacitors: 15 - 30% off nominal value, VLoss 1.2 - 2.4%
I have tested that Chinese instrument against a Siemens metal casing precision capacitor of 90.000 pF 0.5% first and it gladly agreed to the printed on values ;-)
So I believe it was very well necessary to retire ## 1,. 2. and 4. whereas these Good-All seem to be still strong.
Next I will have a look how well the seleniums perform. Let's see!
Regards, Joe
Joe