Questions about Bob A IF Alignment Series on YouTube

[bandersen]

Originally Posted by dtvmcdonald

Sure you can just use a voltmeter and a calibrated signal generator.
But no matter which version of the set you have, you need a bias
box (a 9v battery with a 5 or 10K pot across it) to set the bias voltage
at the junction of R241 and R243 to -4 volts. This is because the DC from the output otherwise backs up to there ... this does not matter at 60 Hz.

Use an analog meter between pins 2 and 3 of V8A.

Then you just sweep the generator slowly by hand to get the patterns shown. Tedious but it works.

You set the contrast control to fix the AGC bias at -4 volts. No need for a battery or external supply.

Tedious? That would be insanely difficult. Rotating the RF gen over about 5-10 MHz, while simultaneously looking at a meter needle swing and translating that into a graph in your mind? While keeping careful note of the response at key frequencies and tweaking coils while doing that?

Get a cheap sweep gen. You can even use the TinySA in sweep mode.