Blue is still the input to the gate of the JFET, red the final output. Green the base of the second transistor of the comparator pair, yellow the signal at the junction of the emitter of 365 and collector of 366. According to the schematic the amplitude there should be 5V. Blue cuts out for anything below 5.2V however. Curious. No idea if I'm onto something.
I only have BF440 on hand. Seems similar enough to serve as an impromptu replacement.
For some odd reason my -20V rail suddenly dropped to -13.5V. I couldn't find the culprit by looking for a heat source
The fault is definitely on rail B. My solution was to feed this rail not from the internal supply but from my lab supply, to then pump more current into it and to hopefully find the culprit through its thermal emissions. Can't find it tho :/
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The thing does oscillate now. This is constant frequency mode, not the sweep. So something is really wrong in the control section
Bun's Lab
The thing does oscillate now. This is constant frequency mode, not the sweep. So something is really wrong in the control section
The wobbliness reacts to percussion. Cold solder joint, bad contact, a transistor or IC with broken bonding.