I inherited an old Crosley 11-207MU cabinet when my Gradfather died. I'm fairly young so I haven't played with tube amps much. When I turn this amp on it does nothing but hum. The volume of the hum doesn't change, even when volume knob turned. I've checked everything I would check on a solid state. Ground, unplugged the phono. I have downloaded the wiring diagrams, just may need a point towards the right direction. Thanks in advance for putting up with a newbie.
Chris

Chris, here's the schematic: http://www.nostalgiaair.org/PagesByModel/224/M0003224.pdf Nice radio - push-pull output, etc.

Replace the electrolytic filter caps, C28A-C28D. You can use separate caps for this 4-unit capacitor. Observe polarity and make sure voltage rating is equal or higher than original.

Unlike solid-state, this radio has very high, lethal DC voltages. Be careful.
Doug

:I inherited an old Crosley 11-207MU cabinet when my Gradfather died. I'm fairly young so I haven't played with tube amps much. When I turn this amp on it does nothing but hum. The volume of the hum doesn't change, even when volume knob turned. I've checked everything I would check on a solid state. Ground, unplugged the phono. I have downloaded the wiring diagrams, just may need a point towards the right direction. Thanks in advance for putting up with a newbie.
: Chris

Thanks, for helping me get a start. I've read about the voltages, and will be sure to watch what I'm doing. I've repaired CRT Monitors/TV's, and appreciate the extra heads up. Thanks

Go to www.tubesandmore.com or www.radiodaze.com for parts.

T

I had been looking @ tubesandmore. I hadn't ben to radiodaze, but I will definitely check it out. Thanks for all the info!
Chris

:Go to www.tubesandmore.com or www.radiodaze.com for parts.
:
:T

One more question. I have the schematic, and have traced all wires to make sure they match, which they do. From what I can tell the 4 unit capacitor is not labeled at all. It may have been replaced once. There are two small round molded paper capacitors that go back to the ground wire. How will all this be tied together. Will all the single electrolytic's be tied back to the 1 ground wire? Thanks

:Chris, here's the schematic: http://www.nostalgiaair.org/PagesByModel/224/M0003224.pdf Nice radio - push-pull output, etc.
:
:Replace the electrolytic filter caps, C28A-C28D. You can use separate caps for this 4-unit capacitor. Observe polarity and make sure voltage rating is equal or higher than original.
:
:Unlike solid-state, this radio has very high, lethal DC voltages. Be careful.
:Doug

Chris - maybe the multi-section e-cap has been replaced with individual caps? Originally, the 4-section e-cap would have been in the metal can shown on top of the chassis in the photo.

C28A, C28B, and C28C are the ones that you need to home in on. C28D, the cathode bypass, is less likely to be causing hum.

If the cap can is still hooked up, then disconnect the leads for C28A, C28B, and C28C, and install replacement, individual caps. Check it, but the can itself should be the connection to chassis ground. Do not parallel new caps with the old. Put the replacement caps under the chassis, and leave the can for ornamentation.

I'm not sure what the two small caps are that you mention, but they aren't involved in the filter cap replacement that we're talking about. You should be able to identify them from their position on the schematic and parts list.
Doug

:One more question. I have the schematic, and have traced all wires to make sure they match, which they do. From what I can tell the 4 unit capacitor is not labeled at all. It may have been replaced once. There are two small round molded paper capacitors that go back to the ground wire. How will all this be tied together. Will all the single electrolytic's be tied back to the 1 ground wire? Thanks
:
::Chris, here's the schematic: http://www.nostalgiaair.org/PagesByModel/224/M0003224.pdf Nice radio - push-pull output, etc.
::
::Replace the electrolytic filter caps, C28A-C28D. You can use separate caps for this 4-unit capacitor. Observe polarity and make sure voltage rating is equal or higher than original.
::
::Unlike solid-state, this radio has very high, lethal DC voltages. Be careful.
::Doug
:
:
:

No, the 4 Section e-cap is still there, with all wires connected to the 4 prongs. (No individual caps. The small caps are going back to C28B in the radio. The schematic does show C28B going to ground. On second look I do see R24, and R25 resistors meeting C28B (on C28A & C28C) on it's way to V5 Tube socket.
Thanks

:Chris - maybe the multi-section e-cap has been replaced with individual caps? Originally, the 4-section e-cap would have been in the metal can shown on top of the chassis in the photo.
:
:C28A, C28B, and C28C are the ones that you need to home in on. C28D, the cathode bypass, is less likely to be causing hum.
:
:If the cap can is still hooked up, then disconnect the leads for C28A, C28B, and C28C, and install replacement, individual caps. Check it, but the can itself should be the connection to chassis ground. Do not parallel new caps with the old. Put the replacement caps under the chassis, and leave the can for ornamentation.
:
:I'm not sure what the two small caps are that you mention, but they aren't involved in the filter cap replacement that we're talking about. You should be able to identify them from their position on the schematic and parts list.
:Doug