Hello All,
I just replaced all the paper and electrolytic capacitors in this radio. It plays well except on very strong stations. The sound overloads and distorts. It sounds like the sound is breaking up when it's tuned to a very strong station. This tells me that the AVC is probably not working. What do I check? I can't find anything wrong.

Thanks,

Dave

The AVC line is at R-5 ( 3.3 Meg ) This is the point where you would find the most negative voltage. Sometimes this resistor climbs up in value.

Warren,
The resistor is a little lower in value than it should be. But that's when measured in circuit. I'll check it again out of circuit and also measure the voltage when the radio is on.

Thanks,

Dave
:The AVC line is at R-5 ( 3.3 Meg ) This is the point where you would find the most negative voltage. Sometimes this resistor climbs up in value.
:

Warren,
Original resistor in circuit: 22 Meg ohms in circuit, 3.3 Meg ohms disconnected from circuit.
New resistor: 3.6 Meg ohms out of circuit 1.6 meg ohms in circuit(it starts out around 22 meg ohms and gradually reduces itself to about 1.6 meg ohms while measuring it in the circuit, due to capacitor action).
Radio still has distorted overloaded sound on very strong stations even after replacing the resistor. There is no way to correct this by tuning or adjusting anything. The tubes test good too. All the connections and resistors are the correct values. Why is it doing this?

Thanks,

Dave
:Warren,
: The resistor is a little lower in value than it should be. But that's when measured in circuit. I'll check it again out of circuit and also measure the voltage when the radio is on.
:
:Thanks,
:
:Dave
::The AVC line is at R-5 ( 3.3 Meg ) This is the point where you would find the most negative voltage. Sometimes this resistor climbs up in value.
::
:
:

Have you done an IF alignment on the set? Also make sure the antenna loop is connected correct. This one has a primary and secondary. The main return line is part of the AVC.

Warren,
The antenna is connected correctly. ALL the other stations, including distant stations sound very good and very clear. I'm not doing an alignment just for one single station. There must be something else wrong.

Thanks,

Dave
:Have you done an IF alignment on the set? Also make sure the antenna loop is connected correct. This one has a primary and secondary. The main return line is part of the AVC.
:

Your radio has a 12SG7 RF amplifier. This is a hot tube to use in the front end. ( more gain than 12SK7 ) If it is only one station that overpowers the radio, that could be normal for your set. It's really a long distance receiver.

Dave,

Have you tried subbing another known good 12SQ7(GT) tube. Tube may test ok in a tester but not work correctly in a radio.

Clifton

:
:Warren,
: The antenna is connected correctly. ALL the other stations, including distant stations sound very good and very clear. I'm not doing an alignment just for one single station. There must be something else wrong.
:
:Thanks,
:
:Dave
::Have you done an IF alignment on the set? Also make sure the antenna loop is connected correct. This one has a primary and secondary. The main return line is part of the AVC.
::
:
:

Be absolutely sure that the new AVC capacitor has not leaked.

Did anyone replace the volume control? This will reduce AVC voltage, as it connects to this circuit.

Anything else to load down the AVC circuit? Upset cathode bias at one of the RF tubes? Upset diode bias at the detector?

My 66X3 performs well on all stations.

I am actually having this problem on the radio in my Silvertone Radio Recorder. I have yet to figure it out, but when I do, I will post. New caps have been used. Volume control is original. Resistors are original and are not drifted.