Hi all,
I spent some more hours with my 3325A.
I made a new effort and studied the service manual from scratch. The main trouble shooting flowchart directed me to group J, so I thoroughly examined everything around U28 to U40.
At least U39 was the culprit! ?It is another analog switch. 1826-0879, hard to find. My REV C Board has many can type opamps and ics. I found a replacement a DG301 from Harris or an TL460 from TI. But the pinout is different. I had to mount the TI reverse and soldered the pins in place.
Now it is working perfect again. I have to calibrate this nice generator, but this is not a big thing. A member here has sent me a detailed calibration guide.
Ralf
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Ralf Rosche