Precision E-200-C Schematic
 

Hi All;
My Precisions Series E-200-C RF-AF Generater is malfunctioning.. Audio no RF, I am looking for a Schematic for it..
The Schematics on line from Bama are not for my model.. They use a 6U8 and a 6AU6, and mine uses a 6C5 and a 6SJ7..
Does anyone have any information on this model ??
THANK YOU Marty

The diagrams are the same. Only the tubes have been changed to 'modernize' it.

Mine uses the later tubes.

Hi All;
I got it fixed..
Bob91343, that's not completely true.. The 6AU6 and the 6SJ7 are basicially the same.. But, the 6C5 and the 6U8 are not even close.. Yes, you could wire only one side of the 6U8, as a 6C5.. And not use the other half of the tube.. But, I couldn't see any reason why..
And Yes, I got the other schematic that uses the tubes, that I have in my unit.. Also, there is another Variation, that uses a 12AU7..
THANK YOU Marty

You are correct, of course. I don't know the function of the pentode part of the 6U8 but the whole thing is so simple it's hard to get very confused.

On the pecking order of signal generators, the E-200 tends to be pretty low. My AN/URM-25D is definitely a step upward, with leveled output, a crystal calibrator, and a few other niceties.

Next maybe comes the HP-606A with its multi-stage setup to avoid FM when using AM, powerful output (up to 3V into 50 Ohms) and excellent shielding.

The Marconi is a versatile one, with both AM and FM, well calibrated for modulation, carrier frequency, and so on.

I recently acquired an HP 8657B that puts all the others to shame, with its oven controlled high stability master oscillator, accurate calibration of carrier and modulation, and carrier frequencies up to beyond 2 GHz. Of course it sold for about $15k when new around 20 years ago but it's a genuine jewel. It doesn't use any 6U8 tubes though. I just hope it never needs repair.

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