Precision E-200-C Schematic

[Geist]

Hi Bob91343;
Yes, I agree that there are more than likely better units, even on the low end.. But, when its all I have, and when it doesn't work, its nice to have something to go by..
Yea, your HP8657b, won't have a 6U8, and I doubt it has any tubes at all, save maybe the CRT, if it has one of those..
And I know there are more modern units that use Transistors and Fets, and IC's, but, since I am testing a tube unit, I wouldn't want to short something with 135 Volts or more.. Where a tube unit would most likely be able to take it, a modern unit won't most likely survive, that kind of voltage.. The Precision Signal Generator has two caps on its front end, before it reaches the output plate of the 6SJ7.. And since it runs at about 200 volts, (the 6SJ7) the 135 wouldn't phase it in the least.. Where as even a 40 volt CMOS would be very unhappy when 135 volts comes down its input, even if it has a 50 volt cap on its front end..
THANK YOU Marty