While I’m waiting for help for compiling/modifying the firmware for my STS-1 tube (practically identical to the SI1G already defined in the code), I’m troubleshooting the high-voltage stage. I’m using firmware made to work with the SBM-20 tube while I have a STS-1 version, but I don’t think that is the reason for having such a low voltage – 15V on the tube!
I took some measurements with the oscilloscope. Could it be the MPSA42 transistor? Or the 2N2907 transistor?
The coil is a quality 2.2 mH, very low resistance, not the green version that looked like a resistor.
Any ideas? Can someone measure same test points on their units?