Pots are all cleaned with DeoxIT D5, and it works much better. Before cleaning, every time I turned one of the pots even a bit, noise would show up on the scope, now everything is clean looking. In the end I decided that since the generator itself cost $30, spending another $30 for DeoxIT 100 didn't seem appropriate
. And these days there are fewer and fewer pots to deoxidize. As a matter of fact, the DeoxIT I used was a good 15 years old, and still basically full.
I noticed that the front panel was supposed to have a 5V micro lamp over the main frequency selector, long since burned, so a new orange LED with proper resistor has taken its place. The lamp was help in place with a blob of transparent silicone, so it was easy to fit a LED in the hole and use hot glue to hold it in place. Power for the lamp came directly from a 7905, so safe to replace the lamp with a lower draw LED (15mA vs 50mA)
While working on it, I realized that the online copies of the Wavetek 190 manual were scanned with decent quality, but never had OCR applied to it, so the PDF was not searchable. I applied OCR and proofread all the manual (just didn't too the schematics, too much work going thru everything there and marginal utility). Unfortunately I can't upload it here, as even compressed it's more than 5Mb. If anyone needs it, or wants to replace some of the online copies, ping me
Next step is calibration. Works well up to ~5MHz, then the waves get asymmetrical. Square waves will always have problems above 10MHz, since the rise/fall time, according to the specs, is <15ns, and I measure 8ns. A trapeziodal would work, but right now there is a lot of ringing, which makes the wave really not that square. Also the triangular wave has a tiny defect at the peaks and valleys above a certain frequency. The manual lists calibration and repair steps, with plenty of expected voltages and waveforms at various points. so a fun project