How far did you get with the oscillator board inductor and did you still use a low hfe 2N4124 transistor successfully ? Also , regarding the inductor based osc plug in board , the base leg of 2N4124 is very close to the negative side (cathode) of D15 1N4148 diode , which looks to be a sensitive area on the pcb for a accidental solder bridge - as you indicated, not sure.
This oscillator inductor appears to have two windings on a single toroid core , this can be seen on the schematic (below) showing footprint 1 thru 4. T3 Pins 1-2 (coil 1) and T3 Pins 3-4 (coil 2). The T3 3-4 coils appear to have ~ 3 windings, while T3 1-2 coil appears to have ~5 windings. Question now, are both windings at 80uh, doubt it. My guess , Pins 1-2 have to be higher uh, while pin 3-4 are lower uh value. Someone supplied a picture of T3 pin and indicated .08Mh or 80uf. the smaller 3 turn winding at a lower uf value. DCR on these coils looks to be very low 1-5 ohms or even less. The key to this inductor is finding the correct ( small ) toriod core, looks to be red colored or T2X-2 with 24 AWG wire. T20 rated for 250khz and up. Finding the correct inductances will take some trial and error ( inductance calculator, LCR Meter, frequency measuring device , scope, dmm ) to get to a stable oscillator at ~250khz freq. Incidentally, as a starting point , the wire gauge for T3, for both windings, looks similar in size to the leads on a 1/4w resistor - pictured below. I estimate with a measurement taken from a 1/4 resistor lead of .5mm or .02" AWG.
Note : VT12/TR12 BSY95a/2N4124 ( Collector ) pin3 , Toroid pin1 - 250khz freq test point , this is taken off the A/C PI 3141 oscillator sub board ( trace side pictured above ) using the T3 inductor, assuming this is also the same test point for other oscillator board running the TLC555 8 pin timer chip. MR2 IS44 or 1N4148 diode in parallel seams to help block any spiked energy from coil T3 pins 1 & 2.
Just tryin to get more info flowing on this project, as it is pretty slim already. Depending on the approach you take , inductors over chips, I don't think this is a easy project for most part. Nevertheless, I like taking the approach that gets me as close to the real circuit as possible.
Also , I'm interpreting this 100k resistor as , 'not implemented ' since there is no pads for this part on the A/C Rev 3.14 pcb , or does it need to be tacked on the board somewhere because of a design error. Its labeled as 'missing' on A/C Rev 3.14 pcb schematic redrawn by a forum member. The original PYE schematic does not show this part. It is not found on the switchboard pcb either. See partial snapshot , Rev 3.14 schem below.
