Quote from: Randy Lahey on May 19, 2024, 06:35:53 PMTransistor pin resistance measurements:
Original Gate - Source: 550 ohms
Original Gate - Drain: 306 ohms
Original Drain - Source: 300 ohms
New Gate - Source: 11M ohms
New Gate - Drain: 320 ohms
New Drain - Source: 10M ohms
The Gate should measure like a diode to Drain or Source. If you measure from Drain to Source you should see the ON Resistance of the JFET (a couple of hundred Ohms). If you short the Gate to one of your meter leads while you are measuring resistance from Drain to Source, the resistance will go down slightly on one lead and rise slightly on the other lead. Those readings of 10M or 11M are probably just the resistance of you fingers across the leads.
From your schematics with the Volume pot at min and max it looks like the JFET is installed with Gate and Source reversed. It may pass a little signal but will have a gain less than one.
See my comments in this thread: https://music-electronics-forum.com/forum/amplification/guitar-amps/build-your-amp/debugging-your-build/20115-please-help-me-out-debugging-my-ruby-bassman-amp
about how to Ohm-check a JFET out of circuit. Note that with the vast majority of JFETs, the Drain and Source are interchangeable.