This page deals with r.f. alignment and how to go about it.


Here we see a chassis with the six rf trimmers you will align,there are usually two for each waveband(sw/mw/lw)



You will need a signal generator to align the rf stages correctly



And a set of plastic trimmer tools.


R.F. ALIGNMENT PROCEDURE-MW

You really need the circuit diagram to do this preferably as its difficult to know which trimmers do what and which ones are for which waveband.

1.ALWAYS MAKE SURE THAT THE I.F'S ARE ALIGNED FIRST.

2.Turn the dail pointer so its at the low frequency end of the dial(the tuning capacitor should be closed)

3.Switch to MW

4.Connect the ground lead of the signal generator(black) to the radio chassis,connect the signal lead of the signal generator(red) via a capacitor of about 250pf to the radios aerial socket.

5.Tune the radio to about 550m(545khz).

6.Tune the signal generator to 545khz,you should hear a tone coming from the radio,if not the local osc will need tuning so the pointer corresponds to the correct frequency on the dial. REMEMBER KEEP THE OUTPUT OF THE SIGNAL GENERATOR AS LOW AS POSSIBLE TO PREVENT THE AUTOMATIC VOLUME CONTROL(AVC) FROM WORKING. Also remember that there are usually only two trimmers per waveband,so you will have to make sure which of these are for the M.W. band.

7.Tune the radio to 200m(1.5mhz)

8.Tune the signal generator to 1.5mhz,adjust if necessary the local oscillator trimmer so that the pointer corresponds with the correct frequency.

9.Repeat process two or three times until happy with performance.

R.F. ALIGNMENT-LW

1.switch radio to lw

2.tune radio to 2000m(150khz)

3.set up signal generator as for mw but tune the generator to 150khz.

4.adjust the appropriate trimmers so the pointer lines up with the correct frequency.

5.tune radio to 1000m(300khz)

6.tune signal generator to 300khz and adjust the trimmers so that the pointer lines up with the correct frequency on the dial.

7.repeat several times until happy with performance.

R.F. ALIGNMENT-SW

1.Switch radio to sw

2.Tune radio to 50m(5mhz)

3.Set up signal generator as for mw but tune generator to 5mhz

4.Adjust the appropriate trimmers so the pointer lines up with the correct frequency.

5.Tune radio to 20m(15mhz)

6.Tune signal generator to 15mhz and adjust the trimmers so that the pointer lines up with the correct frequency on the dial.

7.Repeat several times until satisfied with performance.