I replaced all electrolytics, and other capacitors one at a time back from audio output because the radio came up to a distorted sound on local AM stations when fully powered on the variac. Now when I bring it up I have no sound and B+ is low. What could have failed?

You may have the electrolytics in backwards? All electrolytics in this radio should have their positives facing the rectifier cathode (or the field coil, which is connected to the rectifier cathode).

Distortion (prior to your re-cap) can be caused by a leaky capacitor in the AVC circuit, which reduces AVC voltage and prevents it from reducing RF amplifier sensitivity during reception of strong signals. Leaky audio coupling capacitors can also cause distortion, but the distortion will be present for all signals at all volume levels, and will most likely be present even when the radio is operated below normal voltage.

T.

I was able to get B voltage to about 100 volts on plates, and by adjusting IF transformers and re-routing the antenna wire I got rid of much of the dsitortion and squeals.
But as I brought variac up to 110 to 115, resistor (400 ohms) that comes off first electrolytic negative side to ground got very hot and the rectifier got quie a glow. It is a 6X5 that has been wired in to replace the 1V. What would drwa current to cause this, another resistor?

:You may have the electrolytics in backwards? All electrolytics in this radio should have their positives facing the rectifier cathode (or the field coil, which is connected to the rectifier cathode).
:
:Distortion (prior to your re-cap) can be caused by a leaky capacitor in the AVC circuit, which reduces AVC voltage and prevents it from reducing RF amplifier sensitivity during reception of strong signals. Leaky audio coupling capacitors can also cause distortion, but the distortion will be present for all signals at all volume levels, and will most likely be present even when the radio is operated below normal voltage.
:
:T.

You probably have the electrolytics wired in backwards. Check them.

T.

Really?

I always understood that they would blow up if wired in reverse. (Thankfully, I never experienced this.)

:You probably have the electrolytics wired in backwards. Check them.
:
:T.

....Well, if the rectifier doesn't glow and blow up first.

The positives should face the rectifier cathode and the field coil.

Also, be sure that the electrolytics are rated above the voltage seen in the radio's B circuit. If they are not rated high enough, it is possible that they operated ok with the lower voltage, but then began to break down once the voltage was increased. The break-down process can also occur over a period of time with full voltage, and might not happen right away. Either way, whether the electrolytics be reverse biased or rated inadequately voltage-wise, they can either explode or cause the rectifier plates to glow, or both.

T.

Thomas, I double checked and I have the electrolytics installed with correct polarity. The fact that a 6X5 (using one side) has been wired in the replace the 1V, coul that be a factor in drawing too much?

:....Well, if the rectifier doesn't glow and blow up first.
:
:The positives should face the rectifier cathode and the field coil.
:
:Also, be sure that the electrolytics are rated above the voltage seen in the radio's B circuit. If they are not rated high enough, it is possible that they operated ok with the lower voltage, but then began to break down once the voltage was increased. The break-down process can also occur over a period of time with full voltage, and might not happen right away. Either way, whether the electrolytics be reverse biased or rated inadequately voltage-wise, they can either explode or cause the rectifier plates to glow, or both.
:
:
:T.

Perhaps I've replaced electrolytics of too high value, using 20 to replace 16 and 8.

:Thomas, I double checked and I have the electrolytics installed with correct polarity. The fact that a 6X5 (using one side) has been wired in the replace the 1V, coul that be a factor in drawing too much?
:
::....Well, if the rectifier doesn't glow and blow up first.
::
::The positives should face the rectifier cathode and the field coil.
::
::Also, be sure that the electrolytics are rated above the voltage seen in the radio's B circuit. If they are not rated high enough, it is possible that they operated ok with the lower voltage, but then began to break down once the voltage was increased. The break-down process can also occur over a period of time with full voltage, and might not happen right away. Either way, whether the electrolytics be reverse biased or rated inadequately voltage-wise, they can either explode or cause the rectifier plates to glow, or both.
::
::
::T.

No, that small of a capacitance increase won't affect much. You can parallel the two 6X5 plates. However, one side of the 6X5 should be adeqaute for that small radio. Make sure that your electrolytics are rated well above the voltages found in the radio's B circuit. Also, test the 6X5 to see if it has a heater to cathode short. If that is the case, nothing else is wrong with the radio. If you cannot duplicate the problem with a tube tester, what you can also do is disconnect all wires from the 6X5 cathode terminal (on the socket inside of the radio) and then bring the radio up slowly on a variac. If the plate(s) starts to glow, then the rectifier is indeed faulty. The short may be intermittant, so be aware of that. If you wish, you may put a #47 pilot lamp in series with the wire that goes from the transformer's high voltage winding to the 6X5 plate(s). That will protect the transformer from future shorts, which aren't too infrequent with the 6X5 for some reason. A very good choice as a substitute in this case (since only half wave rectification is necessary) would be to use a 6 volt television damper tube, such as the 6DE4, though filament current draw may be too much. Those tubes have very good heater to cathode insulation, though. There are other good substitutes, too. However, the 6X5 is usually a good performer, as is the 1V, so using a #47 pilot lamp as a fuse should be good enough.

T.