Norm Dresner wrote:


This 741 is the error amplifier with an MJE340 pass transistor which is
supposed to output a regulated +20V based on the zener input. This is an
ancient Tektronix FG501 plug-in function generator which I bought used
knowing that the pilot light came on and that it was otherwise untested.

Norm


Ok, I have the schematic for a SG505 in front of me, which ought to be
similar to your FG501 supply, and what I see is a simple application for
any 741 opamp. The 741 is rated for use to a maximum of 44V in a single
supply circuit, and your circuit has only 30V.

Am I missing something here? Why aren't you simply replacing the opamp?


-Chuck Harris