[Collins] COLLINS R-388/51J-3 FREQUENCY ACCURACY & CALIBRATION

[Park, Ted]

Gentlemen

I am restoring a beautiful old Collins R-388 receiver (military version =
of the Collins 51J-3) serial number 544 and its frequency accuracy =
across the thirty 1 MHz band segments  varies from being right on to =
being off by as much as plus 7 KHz. Most of the band segments that are =
off are off by less than plus 3 KHz. I have obtained and read the April =
1952 version of the Department Of The Army Technical Manual TM 11-854 =
for the Radio Receiver R-388/URR  but even after reading and studying =
the manual it is unclear to me how I can adjust the frequency =
calibration for individual band segments except for a front panel =
mechanical adjustment which will only adjust for +/- 5 KHz. I suspect =
that I may simply have to replace one or more of the crystals for V 105 =
as the crystals may have aged and slightly changed frequency over the =
last 52 years.

Can anyone provide me with guidance who is familiar with the Collins =
R-388? This is the first R-388 I have ever owned or used.

I have previously restored a Collins 51S-1 and I had to replace 5 =
crystals in the 51S-1 to increase its frequency accuracy to where it =
should have been.

Thanks, Ted, K6XN=20