Sir Teh . . . . .
Is your monitoring receiver old school, that lets you tune to any frequency and thereby be able to receive white noise / hiss when tuned off of a station, to a dead spot on the FM band ?.
Or is it digitized and will step to and stop on ONLY active received stations ?
Old style is better in your particular signal seeking situation here.
AND a small portable unit, so that it can be almost kissing the transmitter board.
You mention tuning condenser, but it must be hidden on the other side of the board ? . . . across its air wound companion resonationg coil.
Its now just a matter of setting the receiver atop the unit and off station at the high end of the FM band and slowly sweeping the TC thru its full range to see if you hear QUIETING of the white noise by your incoming transmittted signal.
Next tune the FM receiver to mid band and try the slow transmitter sweep frequency again.
Lastly, place the FM receiver at its lowest received frequenct and do the slow transmitter sweep again.
I'm fully expecting the signal to have been found now . . .if it IS transmitting .
If not, you have the capability to alter the coils effective inductance by compressing its turns to extend your lower frequenct range or by stretching the coil to extend its high frequency range.
Before doing that,. also know that you can alter the low frequency tuning range by the different degree of progressively grasping the center of the coil with thumb and 2 fingers. Try that at high nid and low end of the FM band tests. You will hear the quieting change as you tune past frequency, and can make it sweep up and down by playing with that critical grip level..
Your problem would only be related to the osc xstr, and you did not sub and end up with another xstr nmber with a case lead arrangement that swaps E-B-C connections ? Did you ?
Don't even worry about it NOW, but if the finally working unit will end up not reaching the high end of the FM band, that wound inductance seems one turn too many. Either needing a coil stretching or a turn removal.
73's de Edd