[R-390] Receiver Overload?

[Bill Smith]

I wonder what experts think...

I experience RF overload on the BCST band.  I think I mentioned same when I
first obtained the receiver.  After detecting leakage from E207 on several
bands (measured high resistance to ground when it should have measured
open), I replaced mica capacitors in Z202 and others and the problem seemed
to go away.

But now it is back.  Symptoms are (1) intermod on BCST band.  I wish to
listen to a Los Angeles station from the SFO Bay Area, but with the antenna
hooked directly through a small balun to the balanced input, the station is
obliterated.  If I feed the antenna through a lossy antenna tuner and balun,
signal is heard fine.  Local stations will pin the Carrier Level meter.  Not
hard, but meter will extend beyond 100.

I have measured many resistors in the RF section by testing between the B+
and tube pins, all seem close to values listed in the schematic.  Same with
screen and cathode resistors.

I get 9-10 volts from the agc terminals with strong signals, so there is
apparently plenty of AGC voltage.  I attached a RF choke to the tip of the
VTVM DC probe and verified the same AGC voltage is present at E206 and E207.

Does this sound normal, particularly the 100+ reading from the Carrier Level
meter?  Otherwise, all seems normal (I have removed the IF module and
verified all seems well in that section).

Any suggestions are most welcome.  I will next attach a strong signal
generator to the unit and get better measurements.

73 de Bill, AB6MT
billsmith@ispwest.com