General requirements are a Sweep Oscillator and a Double beam Oscilloscope.

1. Connect double beam oscilloscope as follows:-
a) Earth to earth tag on strip 3 adjacent to the angular bracket.

b) IF ( on Y1 ) to second tag down on strip 3 (grey lead and 10 MOhms resistor).

c) Discriminator ( on Y2 ) to pin 4 of discriminator transformer.

2. The sweep oscillator attenuator should be set to give a trace height the half height of that obtained of this IF when limiting.


3. Connect generator earth to oscilloscope earth and signal to terminal 4 of IFT ( T1 ).


Procedure;

1) Adjust 2nd IF transformer to give trace :-


2) Adjust discriminator transformer to give trace:-



3) Transfer generator o/p to :-

a/ Earth on earth tag adjacent Pin 4 of V3.

b/ Signal to the wire between IF coil and Pin 3 of V3.

Adjust 1st IF transformer to give trace:-


4. Connect aerial to tuner and adjust orange trimmer to give correct tracking.

5. Tune to a transmission and adjust aerial transformer, mixer and IF coil for maximum deflection of tuning indicator.

6. Disconnect aerial and reconnect generator leads as outlined in paragraph 3 ( general ) and adjust 2nd IFT for best shape ( see diagram under 1 above ).

7. Reconnect generator leads as outlined in paragraph 3 above and adjust 1st IFT for best shape ( diagram under 3 ).

8. Adjust bottom core of discriminator to set centre of discriminator trace on marker pip ( diagram under 2 ).

9. Increase generator o/p to maximum. IF trace should be symmetrical about centre of discriminator.


10. Transfer generator leads to aerial terminal via a matching unit ( if necessary ). Tune receiver to 95 MHz and adjust oscillator to give a trace well below limiting level. Adjust IF coil to produce a flat-topped IF trace.


11. Screw IF coil core IN until trace is reduced to half original height. The bottom core of the first IFT is then adjusted to level out top of IF trace.

12. Tune receiver to 88 MHz and adjust sweep oscillator to this. Adjust aerial transformer core to give maximum trace height.

13. Tune receiver to 93 MHz and oscillator to this. Adjust mixer core for maximum IF trace.

14. Tune receiver to 97 MHz and oscillator to this. Adjust aerial trimmers for maximum trace.

15. Repeat 12, 13 and 14 until no improvement is obtained. The generator o/p must be kept below limiting during this operation.

16. Fine adjustment for Radio 1, 2 and 3 etc., can be obtained by adjustment of C8 when cover is fitted.