[Hammarlund] hq180 restoration

[Mike Taylor]

Chris, sounds like the previous owner's method of troubleshooting was to
start disconnecting things until the problem goes away. (Interesting concept
but life isn't that easy). The cap you found disconnected is C128 (1000mf)
which does go to pin 7 of V16 (6AV6). On your schematic, follow the line
from V16-pin 7 to C128. From there the line continues on to guesswhat...pin
2 of Z2! Pin 3 of Z2 goes to V17 (6AQ5) pin 7 or 1 as those two pins are
tied together. Pin 4 of Z2 connects to ground. On the schematic, looking 1/2
inch to the left of V17 you'll see a pair of 500k resistors, a pair of 250mf
caps and a .01mf cap. Notice the dashed line surrounding these components.
That means they're all inside one enclosure. If I remember right, it's a
flat rectangular thing with four leads coming out of one side. (Group please
correct me if I've forgotten what it looks like.) In the radio's chassis,
follow the wire from V16 or V17 to Z2. As for the speaker noise, I think the
first thing I'd do is to pull V16 out of it's socket and see if the  noise
stops. If so, the problem is likely ahead of V16. If not, I'd start checking
the components between V16 and V17 after checking voltage and resistance
measurements on those two tubes. Make sure one of your speaker wires isn't
touching the "mute" screw on the speaker hook-up terminal. C128 is one more
of several wiring errors you've already found. There may be more. It's hard
to find someone else's mistakes. Keep us posted. Mike