[Collins] Collins 75S-1 Receiver Question.

[DW Holtmnan]

Hello,

I'm doing a little maintenance/troubleshooting and have the following 
question that hope fully someone can help me with.

I've removed the Metal cans that cover the RF switches, S2, S3 and S4 
and the associated circuits. The front section,  (the Oscillator) in the 
21 MHZ switch position shows two caps on the schematic, C120 (15PF Mica) 
in parallel with  C75 (8 to 50PF Variable). My radio only has C75, C120 
is not there. Is it left out from the factory? Should I put one in. I 
have looked at the SIL's and there is no mention of this cap. Apparently 
it aligns with the cap missing, but the variable cap is close to it's 
max position, but not maxed out. I know that it will work either way, 
just wondering if other radios have this cap installed, of if there is 
some error in the schematic. My manual is the 9th edition, 15 June 1961.

Thank you in advance for any help.

Best,
DW Holtman
WB7SSN