[Tubester]

Thanks David! I do have that same later prodution model 610 schematic. I've also studied the Philco service bulletins for upgrades. Service bulletin 217B (beginning with run #15) talks about improving oscillator action at 6MC, but only mentions removing resistors (17)/51kohms and (18)/25kohms. In my chassis those resistors are connected to tube 78 grid 3 (plate grid) instead of tube 6A7's cathode. There's no mention of oscillator wiring changes. Therefore, my question is about the wiring at item (8), oscillator. My chassis wiring agrees with the upper part of the schematic regarding the coils at the item (10) and (11) variable trim caps. However, my chassis wiring of the lower coils associated with item (12) and (13) variable trim caps and item (14) fixed cap do not agree, as shown in my 'actual schematic' noted earlier. Trying to confirm the later production Model 610 Philco schematic is the way to go. Probably just need to envoke Occam's razor and trust the Philco schematic. Any other thoughts would be appreciated. Dan