21-04-2013, 08:59 AM
The transformer primaries and C501/R501 remind me of the old style Blocking Oscillator, the discharge rate of C501 being taken care of by the action of the 12AU7 which is adjustable via RV500. If all the components asscotiated with the oscillator and its control circuit are ok and there are no obvious mechanical shorts or open circuit connections then the non functioning would point to excesive secondary loading or shorted turn/leakage within the transformer.
I cannot say with any certainty as to wether or not C518 is crucial to the initial oscillator fire up.
Lawrence.
I cannot say with any certainty as to wether or not C518 is crucial to the initial oscillator fire up.
Lawrence.
