I bought this thing some 10 years ago used and it has worked ok, mainly as an audio generator. I fired it up the other day and the upper ranges seem to output a funky sine wave now. The 10 kHz and 100 kHz ranges output a distorted waveform that does a direction reversal a little bit after going negative of the midpoint. It almost looks like a rectified sine wave, but the waveform is more than half a cycle. I don't see any issues on the other waveforms.
I can play with the range switch and find that turning it slowly can have an impact on the point of the waveform where the reversal occurs. But it doesn't really feel like a switch problem. I would disassemble the switch to see if there are mechanical issues, but it is one of those multi-gang wafer switches with components mounted directly on it and each gang is soldered to the board, a real nightmare to remove. This thing was made to never break, not to be repaired.
I don't have any info on it. The circuit board has some dozens of transistors, a couple of what are likely op amps (metal cans) and well over a hundred passives. I don't know where to begin trying to fix it... other than connectors and switches are the primary point of failure. But even removing and reseating boards looks like a bear in this thing.
Any suggestions on ways to repair this?
I saw the other thread on new units and had looked at some of the little $8 boards on eBay. Funny that there isn't much in between the $8 boards and the $400 boxes. I would have thought this is something that could be done very inexpensively these days. I would use a PC audio output but my signal is outside the 20 kHz upper limit of audio outputs.
Maybe I'll add a simple sig-gen to the prototype circuit I'm building. Lots more than $8 of effort, but I'll know what I'm getting.
Rick