I know nothing about antique radios but I am an inveterate tinkerer and have discovered the source of a problem with my GE Model S-42 Superhet Radio, circa 1930 (??) but I do not have a permanent solution.
The problem is extremely weak volume at max volume setting UNLESS I touch the top of tube UY 224 (located at the far right hand side, rear side of the chassis as viewed from the back), thus apparently providing a suitable ground for part of the circuit.
Any advice would be greatly appreciated. Please contact me at:
toadbarker@yahoo.com
OR
H.W. Barker
PO Box 1231
Greenwood, NS, CANADA
B0P 1N0
Your hand is acting like an antenna when touching the top of this detector stage. Doing this you are bypassing the front end of your radio. Do you have an antenna connected to the radio?
You can get a copy of the schematic here on nostalgiaair and measure voltages. When you have questions about your radio post them here.
Norm
: HELP !!!
: I know nothing about antique radios but I am an inveterate tinkerer and have discovered the source of a problem with my GE Model S-42 Superhet Radio, circa 1930 (??) but I do not have a permanent solution.
: The problem is extremely weak volume at max volume setting UNLESS I touch the top of tube UY 224 (located at the far right hand side, rear side of the chassis as viewed from the back), thus apparently providing a suitable ground for part of the circuit.
: Any advice would be greatly appreciated. Please contact me at:
: toadbarker@yahoo.com
: OR
: H.W. Barker
: PO Box 1231
: Greenwood, NS, CANADA
: B0P 1N0
: Your hand is acting like an antenna when touching the top of this detector stage. Doing this you are bypassing the front end of your radio. Do you have an antenna connected to the radio?
: You can get a copy of the schematic here on nostalgiaair and measure voltages. When you have questions about your radio post them here.
: Norm
:
: : HELP !!!
: : I know nothing about antique radios but I am an inveterate tinkerer and have discovered the source of a problem with my GE Model S-42 Superhet Radio, circa 1930 (??) but I do not have a permanent solution.
: : The problem is extremely weak volume at max volume setting UNLESS I touch the top of tube UY 224 (located at the far right hand side, rear side of the chassis as viewed from the back), thus apparently providing a suitable ground for part of the circuit.
: : Any advice would be greatly appreciated. Please contact me at:
: : toadbarker@yahoo.com
: : OR
: : H.W. Barker
: : PO Box 1231
: : Greenwood, NS, CANADA
: : B0P 1N0
Norm
Thanks for the tip and the quick reply...
Yes, there are TWO antennae at the back of this old girl, but touching (ie grounding??) them does not produce the same result as touching the detector tube as described previously.
I will try to have a look at the schematics as posted but I'm afraid my knowledge of electronics is pretty dismal...
thanks again
toad barker
Norm
:
: Norm
: Thanks for the tip and the quick reply...
: Yes, there are TWO antennae at the back of this old girl, but touching (ie grounding??) them does not produce the same result as touching the detector tube as described previously.
: I will try to have a look at the schematics as posted but I'm afraid my knowledge of electronics is pretty dismal...
: thanks again
: toad barker
: You only have one tube ahead of this circuit, the #35 RF amplifier. Checking voltages on this tube and the coils around it should find the problem. Make sure the tube itself is good. You can do this by reversing the 2 #35 tubes in your radio.
: Norm
: :
: : Norm
:
: : Thanks for the tip and the quick reply...
:
: : Yes, there are TWO antennae at the back of this old girl, but touching (ie grounding??) them does not produce the same result as touching the detector tube as described previously.
:
: : I will try to have a look at the schematics as posted but I'm afraid my knowledge of electronics is pretty dismal...
:
: : thanks again
:
: : toad barker
I agree, just touching the circuit changes the capacity and can either increase or decrease volume. Defective paper caps will cause this effect especially around IF Transformers.
In this case touching the grid cap of the 24A causes stations to be heard. The 24A is called detector but really it's a mixer stage. Signal comes in through the antenna to a 35 tube, RF stage, and then to 24A according to the RCA R-7 and R-9 circuits.
The 35 tube receives the same voltages as the 24A so it should have power. The only things I see in the circuit that would prevent the antenna from having an effect would be the Antenna or RF coil or 35 tube itself. Take a look and see what you think. The circuit can be found on nostalgiaair, in Rider or most often needed 1226-1938 radio diagrams.
Norm
: Norm may want to correct me, but I have a Emerson model 28 from 1934 that acted much like you describe. I did two things to it that brought it to give loud volume: I replaced the paper capacitors and realigned the I.F. transformers. Touching anything that connects into the I.F. transformers loads their circuits and changes their tuning. That change could either increase or decrease the speaker volume as the loading improves or degrades the state of tuning. Paper caps will load these circuits as they become leaky with age. Just replacing them may completely solve the problem. Am I correct, Norm?- Bart
:
: : You only have one tube ahead of this circuit, the #35 RF amplifier. Checking voltages on this tube and the coils around it should find the problem. Make sure the tube itself is good. You can do this by reversing the 2 #35 tubes in your radio.
: : Norm
:
: : :
: : : Norm
:
: :
: : : Thanks for the tip and the quick reply...
:
: :
: : : Yes, there are TWO antennae at the back of this old girl, but touching (ie grounding??) them does not produce the same result as touching the detector tube as described previously.
:
: :
: : : I will try to have a look at the schematics as posted but I'm afraid my knowledge of electronics is pretty dismal...
:
: :
: : : thanks again
:
: :
: : : toad barker