03-11-2016, 09:58 PM
(03-11-2016, 01:37 PM)Mike Watterson Wrote: Check ... if RF (not LO) AM trimmer has been moved, I'd not touch the IF or LO alignment.
I'm not sure I understand the reason for ignoring the Local Oscillator coil - it is just as likely to have been interfered with as any other - and it is easy to reset using broadcast transmissions if an accurate signal generator is not to hand.
I'm quite sure that there are many on here who have quite happily - and accurately - carried out the RF alignment of many AM receivers - including those we built ourselves! - without access to a signal generator.
Of course, I admit there aren't as many AM signals around these days but those that are, as in the past, have a guaranteed accuracy far outstripping the accuracy of any signal generator we might have or desire! Of course, these days, I dare say there are a few synthesised generators sitting on enthusiasts shelves but I'm going back to the days when they didn't even exist!
Even IF alignment should be simple - especially if only one circuit has been touched. FM alignment is, of course, an entirely different matter!
