Here is the schematic for your radio:
http://ww3.nostalgiaair.org/schematics/GHU/_GHU_6-9.gif
Check voltages on pins #2 and #3 of the 42 tube. These should be over 200 volts DC.
Norm
:My radio plays but has very little volume. Could someone tell me where to start checking voltages or looking to find the problem?
:Thanks very much
Hi Norm,
I checked the voltage to ea of the wires going to the speaker coil, which I believe are pins #2 and #3. #2 reads 155v to chassis and #3 reads 191 to chassis.
While the volume is low, the sound is real good, but as I turn the volume knob up, it starts to distort and the volume does come up a little. Is there another check I can make or is this telling me the power output tube is bad or very weak?
THANKS
Your 42 tube may be drawing excessive current causing voltage to be lower. That is too much of a difference in voltage between pin #2 and #3.
By your readings here is what I think is causing the problem. Grid #1, pin #4, must be 15 to 20 volts negative in relation to cathode, pin #5. If it's zero or positive your 42 will draw excessive current and distort.
There will be a capacitor connected to pin #4. It may be leaky causing the grid to go positive. If you find grid #1 isn't negative replace this cap. Volume & voltage should increase and distortion will be gone.
Norm
::Hi Jim
::
:: Here is the schematic for your radio:
::
::http://ww3.nostalgiaair.org/schematics/GHU/_GHU_6-9.gif
::
:: Check voltages on pins #2 and #3 of the 42 tube. These should be over 200 volts DC.
::
::Norm
::
:::My radio plays but has very little volume. Could someone tell me where to start checking voltages or looking to find the problem?
:::Thanks very much
:
:Hi Norm,
:I checked the voltage to ea of the wires going to the speaker coil, which I believe are pins #2 and #3. #2 reads 155v to chassis and #3 reads 191 to chassis.
:While the volume is low, the sound is real good, but as I turn the volume knob up, it starts to distort and the volume does come up a little. Is there another check I can make or is this telling me the power output tube is bad or very weak?
:THANKS
Norm
I do have another question about the Grunow 580. On the schematic, it shows the Ant and Doublet connections for the incoming RF signal. Is the Ant the antenna conection for the C band and the Doublet the antenna connection for A and B bands?
THANKS
Jim
:
Correct, by the schematic Ant is for band C and Doublet, A & B.
Norm
:::Hi Jim
:::
::: Your 42 tube may be drawing excessive current causing voltage to be lower. That is too much of a difference in voltage between pin #2 and #3.
:::
::: By your readings here is what I think is causing the problem. Grid #1, pin #4, must be 15 to 20 volts negative in relation to cathode, pin #5. If it's zero or positive your 42 will draw excessive current and distort.
:::
::: There will be a capacitor connected to pin #4. It may be leaky causing the grid to go positive. If you find grid #1 isn't negative replace this cap. Volume & voltage should increase and distortion will be gone:
:::
:::Norm
:::
:::::Hi Jim
:::::
::::: Here is the schematic for your radio:
:::::
:::::http://ww3.nostalgiaair.org/schematics/GHU/_GHU_6-9.gif
:::::
::::: Check voltages on pins #2 and #3 of the 42 tube. These should be over 200 volts DC.
:::::
:::::Norm
:::::
::::::My radio plays but has very little volume. Could someone tell me where to start checking voltages or looking to find the problem?
::::::Thanks very much
::::
::::Hi Norm,
::::I checked the voltage to ea of the wires going to the speaker coil, which I believe are pins #2 and #3. #2 reads 155v to chassis and #3 reads 191 to chassis.
::::While the volume is low, the sound is real good, but as I turn the volume knob up, it starts to distort and the volume does come up a little. Is there another check I can make or is this telling me the power output tube is bad or very weak?
::::THANKS
:::Hi Norm
::You were exactly right! The voltages came up and the sound is great!!
::THANKS again
::Jim
:
:Norm
:I do have another question about the Grunow 580. On the schematic, it shows the Ant and Doublet connections for the incoming RF signal. Is the Ant the antenna conection for the C band and the Doublet the antenna connection for A and B bands?
:THANKS
:Jim
::