Quote:
Originally Posted by Ian - G4JQT
the set was motor-boating with the volume turned up.
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I had a very similar problem with a 1938 Philips 470A. It uses a low IF (120khz I think from memory) and after I'd done the basic restoration I peaked the IF's and it had amazing gain but tended to go very unstable at the HF end of MW. I
should have read the alignment instructions properly......
It clearly states that you have to damp the preceding IF secondary with a resistor before trimming the following IF....Everything was fine after doing that. You can also get a similar effect with a radio that's supposed to have staggered IF's when they are all aligned to the same frequency.