[R-390] IF deck resistance tables in Y2K

[Norman Ryan via R-390]

Hi, Jim,
Yes, 50 ohms (+/- 10%) across either end of a mechanical filter is correct.
73Norman     From: JAMES GREEN <jagreen3 at sbcglobal.net>
 To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net> 
 Sent: Friday, May 8, 2015 5:54 PM
 Subject: [R-390] IF deck resistance tables in Y2K
   
I thought I had finished the cleaning and restoration of all the modules for Caphart R-390A. I didn't want to put the face-plate back on until I had the thing re-painted. Whilst awaiting my next pay-check to fund the purchase of paint and such I decided to go through the resistance checks of the pins on the connectors. I found tables for this in the Y2K manual.
I started with the IF deck and found one discrepancy that was related to a mod I made to the AGC circuit. No problem there. However, when I check the resistance of pin 6 of j512on the IF deck I get about 50 Ohms to ground. The table says it's supposed to be infinite.
I traced Pin 6 to R-507 a 22K resistor. From there it goes to the common legs on the top ends of the 4 mechanical filters. from there it goes to the rear of S503. I see nowhere where this circuit ever reaches ground. Therefore it should be infinite. I de-soldered the top ends of all the filters and went so far as to remove one of them. When I measure across the end lugs of my filters they all measure about 50 ohms. Is this correct?
Pin 6 of j512 also goes through R-516 (22k) to T501 then to pin 1 of V503 the 3rd IF amp. Should I suspect a problem in T501?
Either way I should be going through a 22k resistor.
I will keep scratching my head and poking about, but any ideas would be helpful. Is it possible the table in the Y2K manual is wrong?
Jim