I just bought a cheap Wavetek model 25 off of eBay and powering it up it had no output (frequency counter reading 0, doesn’t respond to the frequency adjust knob).
Opened it up, found 2 blown fuses (500mA slow blow PICO fuses) immediately ahead of the rectifier for the 25v supply. Further investigation I found 4 burned out resistors between the output transistors (2n2219) and the output attenuators. They hadn’t opened up, one ohms, other 3 between 100-110 ohms. They were marked R128-131, I assume that they are the ones setting the output impedance?
This was a quick 20 minute check out, so I haven’t seen any other apparent damage. I am guessing someone tried turning it up to its maximum output and connected a large load on the output and the resistors and fuses went before there was more carnage. My thought is to replace the burned up resistors and open fuses, check the output transistors, and see if it comes back to life.
I can’t find a schematic, so I’m hoping that perhaps someone has one or can at least tell me if I’m barking up the right tree or can suggest anything else I should investigate before powering it up again.