[R-390] R-390 IF Deck

[Byron Tatum]

Hello-    I picked up a nice condition clean R-390 IF deck, checked it out and got selected tubes in it, and tested it in an R-391 receiver I have here. Allowed it to run about an hour. It is working well as best I can tell but I do have one issue that bothers me. Based on the carrier meter reading the 8 khz BW position is about 12 dB down from the 2,4 and 16 khz positions (these 3 positions are all fairly close in reading).    I have studied the theory of this IF deck and how the 8 khz BW is done. I have carefully gone through the IF alignment procedure as follows -        1. Fed in 455.000 khz from generator through receiver test point on RF deck
        2. Placed BW in 0.1 Khz position and tuned gen for max reading (I assume this is done to align IF for the particular freq of crystal in crystal filter Z-501). Leave gen set here.        3. Placed BW in 2 khz position and adjusted T-506,505, 504, 503, 502 for max reading on VTVM connected to diode load terminal on rear panel.        4. Placed BW in 8 khz position and adjust T-501 for max.Have done this several times but get same results. 
Another question I have is in regard to the glass metal sealed capacitors throughout this deck. Friends have told me they have never seen a bad one, some of them have many years and much gear using them.       I did replace the pair of 1.0 ufd at 400 vdc oil caps with high quality film, and dotted silver mica caps (100, 180 pF) going to ground off of pins 8,9 of V-507 limiter and C-543 (220 pF) going from Z-503 to AGC rectifier V-510. Have not replaced any of these same type caps in RF circuits.Thanks,Byron W5FH