I'm working on a Collins 51J1. Originally came to me with a LOUD HUM but that was taken care of. Also had a very stiff band switch, resolved as well with some drops of machine lube (sewing machine oil). It's receiving on the first 3 lowest bands very well or those being the broadcast band and 2 above that confirmed. All other bands have a bit of noise but no reception and can receive the xtal calibrator signal when turned on.

Seeing as how I'm new to Collins receiver repair but not new to boat anchor and old radio repair, what could I do to fix the issue.

Thanks and 74 de,

Gary/N9VU