V16 is the 6AQ5 "Power Output" tube in the HQ-180A. The cathode of this tube has a 430 ohm resistor and a capacitor to ground. Some drawings indicate that this capacitor is C82D -- a 40uF section of the main filter capacitor can. Other drawings show this capacitor as a 25uF/25v electrolytic. In front of me I have two HQ-180A's. One of them has the 25uF/25v electrolytic installed, the other has only the resistor and no capacitor at all. Both HQ-180A's have the three-section main filter capacitor -- there is no section "D".
So, what's correct? Should there be a capacitor on the cathode of V16 to ground, or did Hammarlund eliminate that in a later version of the radio? I'm not able to find a schematic that doesn't show this capacitor, but there are so many different manuals and versions out there I really can't be sure.
73, Steve - KW4H
Could you have meant V17?
I usually replace the 430 ohm cathode resistor with a 470 ohm 1W and the capacitor with a 47 uF 50V electrolytic. It is there to prevent negative feedback and stabilize the bias.
Phil - AC0OB