Quote:
Originally Posted by Electronic M
Local oscillator alignment is usually what causes off frequency tuning, though if this has AFC try turning it off to verify local oscillator doesn't snap back to normal.... AFC takes detector voltage and uses it to pull the local osc to peak signal... If the AFC bus is wildly wrong it might be able to feign a non-existent local osc alignment issue.
Not a bad idea to atleast check IF pass band with a generator too.
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Yes this radio does have AFC but it acts like its not working (or non-existent), The pointer itself also looks like it might be slighly off because when I turn the tuner knob the pointer at the bottom seems like its in the right spot but then at the top its way off, the weird thing about this radio is that it seemed like it might of been virgin (never touched electrically except to change some tubes.)
But then I saw that the retaining nut that fastened the tuning dial to the cabinet was missing which tells me that the chassis was removed at one point in time, but I don't think it was for component replacement (as all of the capacitors and resistors were original) I think it was to attempt an alignment (also the tuning string was broken going from the tuning knob to the pulley.)
So quite possibly someone attempted to do an alignment on this radio but didn't know what they were doing and screwed something up with the local oscillator adjustments and also the AFC circuitry.
I'm going to attempt to look into what you suggested and also the alignment as well, I'll need to see if I can find a service manual for this radio so I can find the alignment instructions.