Just finished the recap on the 5905 chassis and brought the power up. Tuning eye is finding signals but no sound, suspecting bad voice coil I jump the terminals under the chassis witha little test speaker. Set works and is very sensitive and selective, but sound is still low. While letting the set play, I find the 6f6 tube(brand new and tested) is hot enough to smoke the fresh outer paint! I check voltages and ternminals 3+4 are 50 volts high. terminal 5 is about 20 volts high and 7 (I believe filament showing 6.2 on schematic)is at 0 volts. I decided to survey the rest of the terminals
in the set and found that most are about 50 volts high and the filament line is a little low at 5.8 volts. Checked the transformer. It is factory original, and giving me an output of 355 constant volts to the rectifier which is supposed to have 298 (from schematic). It does not overheat and aside from the normal hum / I hear no internal arcing. Does anyone know what might be going on here to get that 6f6 so hot that it could boil water. Are these high voltages a sign of the manufacturing, and
not a problem or could this be something else? Any help would be appreciated. I am going to have the speaker sent out for reconing and to get the voice coil rewound, but I'm beginning to believe a greater problem exists.

Jusitn

Hi Justin

The voltage on Pin #5, grid 1 must be negative in relation to Pin #8, cathode by 15 - 20 volts. If it is not the 6F6 will draw excessive current, overheat and distort. You mention using a 6F6 tube (metal). These will run hotter than the 6F6G which is larger.

High B+ voltage may be caused by high line voltage and new components. This isn't a problem as long as the 6F6 plate remains below 300 volts.

Norm

: Just finished the recap on the 5905 chassis and brought the power up. Tuning eye is finding signals but no sound, suspecting bad voice coil I jump the terminals under the chassis witha little test speaker. Set works and is very sensitive and selective, but sound is still low. While letting the set play, I find the 6f6 tube(brand new and tested) is hot enough to smoke the fresh outer paint! I check voltages and ternminals 3+4 are 50 volts high. terminal 5 is about 20 volts high and 7 (I believe filament showing 6.2 on schematic)is at 0 volts. I decided to survey the rest of the terminals
: in the set and found that most are about 50 volts high and the filament line is a little low at 5.8 volts. Checked the transformer. It is factory original, and giving me an output of 355 constant volts to the rectifier which is supposed to have 298 (from schematic). It does not overheat and aside from the normal hum / I hear no internal arcing. Does anyone know what might be going on here to get that 6f6 so hot that it could boil water. Are these high voltages a sign of the manufacturing, and
: not a problem or could this be something else? Any help would be appreciated. I am going to have the speaker sent out for reconing and to get the voice coil rewound, but I'm beginning to believe a greater problem exists.

: Jusitn

Have also just found that the speaker output transformer

is most likely shot. It has continuity on the speaker winding

but not the winding heading to the set. (Infinite resistance, so I suppose it opened up) Correct me guys if I'm wrong, but I'm assuming

that it should also be continuous when I check the leads.

Most likely the culprit for the loss of sound... Would this wreck havoc on my 6F6 voltages like

I'm experiencing?

Justin

The primary of the output transformer should have continuity but higher resistance than the speaker side. If it is open the plate of 6F6, pin #3, will not have voltage and the screen may be glowing red hot.

Norm

: Have also just found that the speaker output transformer

: is most likely shot. It has continuity on the speaker winding

: but not the winding heading to the set. (Infinite resistance, so I suppose it opened up) Correct me guys if I'm wrong, but I'm assuming

: that it should also be continuous when I check the leads.

: Most likely the culprit for the loss of sound... Would this wreck havoc on my 6F6 voltages like

: I'm experiencing?

: Justin