Receiver Oscillator Multiplier Board

I know of at least three version of the Oscillator Multiplier Board .I have only use the later model oscillator boards. The earlier boards have 3 tuning coils and the middle model has a C406 capacitor in place of L6. The components of the middle model board are number using three digits and the later model uses one or two digits. I have used both numbering systems on the drawing.

On Coil L1 short out 1.5 turns form Center of coil. On coil L2 short out 1 turn from outside. On L403 short out 1 turn from outside. No. 30 solid wire works well for shorts.

Remove and discard the following capacitor C12

The oscillator may work but the get maximum performance you can:

     •     Replace Q1 with a 2N2857

     •     Replace Q2 with aMRF517

The picture below shows an easier modification that works equally well. Short the three coils as described above and remove capacitor C7.The L1 and L2 capacitors have two points on the 360 degree tuning radius that seem the tune equally but you have to keep trying different combinations to get the mixer to tune to specifications. If you don't get the combinations correct, it will only tune to 2.5 MV. If you get the combination correct it should tune to .25 MV.

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