I tried to reply to the post that answered my question about recaping this radio....The reply did'nt seem to work.
I put in all new discrete filter caps all rated at 450 volts and all the other caps...Anyway the AM and phono work but the FM is dead...Also the 8200 ohm resistor from one leg on the AM/FM/Phono switch to ground fried and broke in half...That resistor is taken out of the circuit when the switch is in FM position I replaced it with a couple of 10 watt resistors in paralel to equal 8300 ohs and that gets so hot I can't touch it. With the switch on AM I read 125 volts on the hot side of that resistor. I do not have a tube tester or a signal gererator. I'm thinking something is drawing way to much current for that resistor to fry....I need hopefully some answers in what to check. The AM plays great even with that resistor out of the circuit....I don't even get any 'white' noise in the FM position. Thanks for any help any one can give me.
-Bill

:I tried to reply to the post that answered my question about recaping this radio....The reply did'nt seem to work.
: I put in all new discrete filter caps all rated at 450 volts and all the other caps...Anyway the AM and phono work but the FM is dead...Also the 8200 ohm resistor from one leg on the AM/FM/Phono switch to ground fried and broke in half...That resistor is taken out of the circuit when the switch is in FM position I replaced it with a couple of 10 watt resistors in paralel to equal 8300 ohs and that gets so hot I can't touch it. With the switch on AM I read 125 volts on the hot side of that resistor. I do not have a tube tester or a signal gererator. I'm thinking something is drawing way to much current for that resistor to fry....I need hopefully some answers in what to check. The AM plays great even with that resistor out of the circuit....I don't even get any 'white' noise in the FM position. Thanks for any help any one can give me.
:-Bill
:
= = = = = =

Sounds like a considerable amount of work was done on this set vis a vis capacitor replacement... so, there is always the opportunity for a solder splash or misplaced lead to have reared its ugly head in the form of a dead short from B+ to somewhere that it does not belong.

Possibly, but by no means certainly, the resistor incineration is related to the dead FM function. This symptom suggests that B+ that should go to the FM stage(s) is getting misdirected, most likely by the means just described.

One common reason for one mode or the other smoking a resistor is a shorted bypass cap on the B+ to that section. This essentially puts a dead short from the selected (FM or AM) section's B+ bus to ground. Usually the guilty caps are larger, 0.1 uF units. Since it was implied that all caps have been replaced, this is probably not the problem.

I would CAREFULLY examine the mode switch for errant solder globs or splashes, then check every new part for good lead dress (i.e., no leads touching). If no luck, you are going to have to break out the ohmmeter and track down the load to its source. This shouldn't be too tough since you have a good schematic with which to work.

You MUST find the short before you proceed with troubleshooting the FM section. One war at a time, if you will.

::I tried to reply to the post that answered my question about recaping this radio....The reply did'nt seem to work.
:: I put in all new discrete filter caps all rated at 450 volts and all the other caps...Anyway the AM and phono work but the FM is dead...Also the 8200 ohm resistor from one leg on the AM/FM/Phono switch to ground fried and broke in half...That resistor is taken out of the circuit when the switch is in FM position I replaced it with a couple of 10 watt resistors in paralel to equal 8300 ohs and that gets so hot I can't touch it. With the switch on AM I read 125 volts on the hot side of that resistor. I do not have a tube tester or a signal gererator. I'm thinking something is drawing way to much current for that resistor to fry....I need hopefully some answers in what to check. The AM plays great even with that resistor out of the circuit....I don't even get any 'white' noise in the FM position. Thanks for any help any one can give me.
::-Bill
::
:= = = = = =
:
:Sounds like a considerable amount of work was done on this set vis a vis capacitor replacement... so, there is always the opportunity for a solder splash or misplaced lead to have reared its ugly head in the form of a dead short from B+ to somewhere that it does not belong.
:
:Possibly, but by no means certainly, the resistor incineration is related to the dead FM function. This symptom suggests that B+ that should go to the FM stage(s) is getting misdirected, most likely by the means just described.
:
:One common reason for one mode or the other smoking a resistor is a shorted bypass cap on the B+ to that section. This essentially puts a dead short from the selected (FM or AM) section's B+ bus to ground. Usually the guilty caps are larger, 0.1 uF units. Since it was implied that all caps have been replaced, this is probably not the problem.
:
:I would CAREFULLY examine the mode switch for errant solder globs or splashes, then check every new part for good lead dress (i.e., no leads touching). If no luck, you are going to have to break out the ohmmeter and track down the load to its source. This shouldn't be too tough since you have a good schematic with which to work.
:
:You MUST find the short before you proceed with troubleshooting the FM section. One war at a time, if you will.
:
Tom: Thanks for the feedback. I replaced each new part one at a time and double checked all my solder connections. All the caps were replaced with new parts and none get hot while operating the set. When the selector switch is in the FM position that resistor that burnt is disconected from the circuit so there is no voltage to it....It gets 125 volts to the hot end in the AM position. AM works great but FM is totally dead. I hate to unsolder all the leads to all the IF transformers to check for shorts. I was really wanting to get this set working on FM as there is nothing on AM any more.

:::I tried to reply to the post that answered my question about recaping this radio....The reply did'nt seem to work.
::: I put in all new discrete filter caps all rated at 450 volts and all the other caps...Anyway the AM and phono work but the FM is dead...Also the 8200 ohm resistor from one leg on the AM/FM/Phono switch to ground fried and broke in half...That resistor is taken out of the circuit when the switch is in FM position I replaced it with a couple of 10 watt resistors in paralel to equal 8300 ohs and that gets so hot I can't touch it. With the switch on AM I read 125 volts on the hot side of that resistor. I do not have a tube tester or a signal gererator. I'm thinking something is drawing way to much current for that resistor to fry....I need hopefully some answers in what to check. The AM plays great even with that resistor out of the circuit....I don't even get any 'white' noise in the FM position. Thanks for any help any one can give me.
:::-Bill
:::
::= = = = = =
::
::Sounds like a considerable amount of work was done on this set vis a vis capacitor replacement... so, there is always the opportunity for a solder splash or misplaced lead to have reared its ugly head in the form of a dead short from B+ to somewhere that it does not belong.
::
::Possibly, but by no means certainly, the resistor incineration is related to the dead FM function. This symptom suggests that B+ that should go to the FM stage(s) is getting misdirected, most likely by the means just described.
::
::One common reason for one mode or the other smoking a resistor is a shorted bypass cap on the B+ to that section. This essentially puts a dead short from the selected (FM or AM) section's B+ bus to ground. Usually the guilty caps are larger, 0.1 uF units. Since it was implied that all caps have been replaced, this is probably not the problem.
::
::I would CAREFULLY examine the mode switch for errant solder globs or splashes, then check every new part for good lead dress (i.e., no leads touching). If no luck, you are going to have to break out the ohmmeter and track down the load to its source. This shouldn't be too tough since you have a good schematic with which to work.
::
::You MUST find the short before you proceed with troubleshooting the FM section. One war at a time, if you will.
::
:Tom: Thanks for the feedback. I replaced each new part one at a time and double checked all my solder connections. All the caps were replaced with new parts and none get hot while operating the set. When the selector switch is in the FM position that resistor that burnt is disconected from the circuit so there is no voltage to it....It gets 125 volts to the hot end in the AM position. AM works great but FM is totally dead. I hate to unsolder all the leads to all the IF transformers to check for shorts. I was really wanting to get this set working on FM as there is nothing on AM any more.
:
I did forget one thing.....I did not replace the mica capacitors as I was told they never go bad. Is that true that they never go bad ? Thanks again.
-Bill

::Tom: Thanks for the feedback. I replaced each new part one at a time and double checked all my solder connections. All the caps were replaced with new parts and none get hot while operating the set. When the selector switch is in the FM position that resistor that burnt is disconected from the circuit so there is no voltage to it....It gets 125 volts to the hot end in the AM position. AM works great but FM is totally dead. I hate to unsolder all the leads to all the IF transformers to check for shorts. I was really wanting to get this set working on FM as there is nothing on AM any more.
::
:I did forget one thing.....I did not replace the mica capacitors as I was told they never go bad. Is that true that they never go bad ? Thanks again.
:-Bill
:
= = = = = =

Fixed mica caps CAN go bad but their failure rate is far less than that of contemporary tubular wax-paper/foil caps, probably due to the strength and durability of the mica dielectric and their hermetically-sealed construction. I would eliminate all other suspects before thinking about indicting a fixed mica cap. An open cap is often hard to diagnose short of just replacing it. A leaky or shorted cap is much easier- it will pass DC voltage, acting more like a resistor than a capacitor.