[Collins] 75A-4 BFO

[wabate]

First thanks to those who helped me with my earlier question on my A4 
meter.  Looks like the meter is stock but the clip that holds the pilot 
light is missing.  I fabricated one.

The next order of business is the passband tuning.  It does not track 
the main tuning well.  The spec I read says that the frequency should 
not change more than 50 HZ when tuned throughout the range.  Is that 
realistic?  Mine is much worse than that.  Probably a few hundred HZ. 
I've read the alignment a half dozen times.  I think I follow it OK.  I 
tried recentering the knob but that did not help.  I tried adjusting 
L-31 as the simple approach and that did not help so it looks like I'm 
in for the "difficult" approach.  I don't have the 6 KC filter so I will 
use the 3.1 and limit the tuning range to 1.5 instead of 2.5.  I will 
hook of a frequency counter to the phones terminal and start tweaking.

Anyone done this before?  Tips?  I have not seen any write ups on this.

Thanks,

Bill, K3PGB