Anyone have experience repairing an HP3325B synthesized generator?

I don't know the answer either. My best guess is that it could be some sort of memory that retains the settings of all the knobs and switches during a power-down and that those values are used on the next power-up so that all the knobs and switches will be set to deliver the same values as when it was switched off. This would suggest that the knobs and switches rotate continuously and generate square waves, like the two pulse-generating wheels inside an old-fashioned mouse. The extra bits and pieces may be a hold-off system whereby the voltages applied to the delicate parts have to reach and remain at a certain voltage level and for a certain length of time before being applied to the rest of the circuit. After all, if the 5 volt peak-to-peak maximum input socket on the equipment that is being calibrated is still connected after a power-down, you wouldn't want to be suppying hundreds of volts to it during power-up. It might also do a similar job on power-down, as the voltages will be all over the place as the power fades away.

I had difficulty viewing the circuit diagram as it is blurred in places and very blurred in others. Can you do it again with the camera on a tripod and the shutter release operated remotely? I have found a desktop music stand to be very useful when standing manuals and diagrams etc nearly upright. The dark part (bottom centre) doesn't help either. Other useful info would be an approximate date of manufacture and the part numbers of some of the other devices especially the two big ones shown end-to-end in the dark area. Also, are there any crystals, and if so what is their resonant frequency? It is just possible that there is a phase-locked-loop in there somewhere.

Final thought - "NV RAM" could be a very early version of "EEPROM", especially if it is written to on power-down and read on power-up. If that is the case then both power-up and power-down might take slightly longer than expected.

I don't know the answer either. My best guess is that it could be some sort of memory that retains the settings of all the knobs and switches during a power-down and that those values are used on the next power-up so that all the knobs and switches will be set to deliver the same values as when it was switched off. This would suggest that the knobs and switches rotate continuously and generate square waves, like the two pulse-generating wheels inside an old-fashioned mouse. The extra bits and pieces may be a hold-off system whereby the voltages applied to the delicate parts have to reach and remain at a certain voltage level and for a certain length of time before being applied to the rest of the circuit. After all, if the 5 volt peak-to-peak maximum input socket on the equipment that is being calibrated is still connected after a power-down, you wouldn't want to be suppying hundreds of volts to it during power-up. It might also do a similar job on power-down, as the voltages will be all over the place as the power fades away.

I had difficulty viewing the circuit diagram as it is blurred in places and very blurred in others. Can you do it again with the camera on a tripod and the shutter release operated remotely? I have found a desktop music stand to be very useful when standing manuals and diagrams etc nearly upright. The dark part (bottom centre) doesn't help either. Other useful info would be an approximate date of manufacture and the part numbers of some of the other devices especially the two big ones shown end-to-end in the dark area. Also, are there any crystals, and if so what is their resonant frequency? It is just possible that there is a phase-locked-loop in there somewhere.

Final thought - "NV RAM" could be a very early version of "EEPROM", especially if it is written to on power-down and read on power-up. If that is the case then both power-up and power-down might take slightly longer than expected.

Blast! Just had another thought! Always the same, I press the Log Out button and immediately think of something else.

The model number HP3325B might be part of the mystery. Assuming there is a HP3325A, C, D, etc, then different fixed parameters could be stored in the NV RAM for different models. In which case don't take the battery out just yet!