I have a Crosley model 635. I replaced the electrolytic and paper caps due to a hum. The hum is still present and after playing for awhile, the transformer gets quite hot. Any help on this would be greatly appreciated.

:I have a Crosley model 635. I replaced the electrolytic and paper caps due to a hum. The hum is still present and after playing for awhile, the transformer gets quite hot. Any help on this would be greatly appreciated.
:

Chuck:
I haven't looked at the schematic yet, but you are describing a B+ short pretty accurately. Put an Ohmmeter on the B+ line and check it first. Now I'll study the schematic and see what else may lay in store.
Lewis

::I have a Crosley model 635. I replaced the electrolytic and paper caps due to a hum. The hum is still present and after playing for awhile, the transformer gets quite hot. Any help on this would be greatly appreciated.
::
:
:
:Chuck:
:I haven't looked at the schematic yet, but you are describing a B+ short pretty accurately. Put an Ohmmeter on the B+ line and check it first. Now I'll study the schematic and see what else may lay in store.
:Lewis
:
Before you connect the ohm-meter, make sure the power is off and the capacitors are discharged.
Rich

::I have a Crosley model 635. I replaced the electrolytic and paper caps due to a hum. The hum is still present and after playing for awhile, the transformer gets quite hot. Any help on this would be greatly appreciated.
::
:
:
:Chuck:
:I haven't looked at the schematic yet, but you are describing a B+ short pretty accurately. Put an Ohmmeter on the B+ line and check it first. Now I'll study the schematic and see what else may lay in store.
:Lewis
:

:::I have a Crosley model 635. I replaced the electrolytic and paper caps due to a hum. The hum is still present and after playing for awhile, the transformer gets quite hot. Any help on this would be greatly appreciated.
:::
::
::
::Chuck:
::I haven't looked at the schematic yet, but you are describing a B+ short pretty accurately. Put an Ohmmeter on the B+ line and check it first. Now I'll study the schematic and see what else may lay in store.
::Lewis: I 'm not sure where to check. I do have continuity to chassis from both plate pins for the rectifier tube (80). I didn't find any issues with any wiring or connections.
::
:
:

::::I have a Crosley model 635. I replaced the electrolytic and paper caps due to a hum. The hum is still present and after playing for awhile, the transformer gets quite hot. Any help on this would be greatly appreciated.
::::
:::
:::
:::Chuck:
:::I haven't looked at the schematic yet, but you are describing a B+ short pretty accurately. Put an Ohmmeter on the B+ line and check it first. Now I'll study the schematic and see what else may lay in store.
:::Lewis: I 'm not sure where to check. I do have continuity to chassis from both plate pins for the rectifier tube (80). I didn't find any issues with any wiring or connections.
Chuck:

Hokay, how 'bout pull all the tubes, and see what happens. Then, if all stays cool, the filament circuit is ok. Insert the 80, and see if the xfmr gets hot, then the output stage, etc. Maybe a process of elimination will find the problem.
Lewis

Is the hum coming thru the speaker, or is the transformer vibrating so hard you can hear it?

You could use the dim bulb test to determine if there is a short.
A 100 watt light bulb is wired so that the bulb is on one leg of the power cord. Google 'dim bulb test'. This test tells you if excessive current is being drawn, indicating a short.

Try this first with the tubes removed as suggested by Lewis.
Do not leave the transformer powered up for any longer than necessary, as it could be on the verge of self-destruction.

I recommend installing a 1 amp slo-blow fuse on the power cord of any radio with a transformer. The fuse will blow before the transformer can go into melt-down.

:Is the hum coming thru the speaker, or is the transformer vibrating so hard you can hear it?
:
:You could use the dim bulb test to determine if there is a short.
:A 100 watt light bulb is wired so that the bulb is on one leg of the power cord. Google 'dim bulb test'. This test tells you if excessive current is being drawn, indicating a short.
:
:Try this first with the tubes removed as suggested by Lewis.
:Do not leave the transformer powered up for any longer than necessary, as it could be on the verge of self-destruction.
:
:I recommend installing a 1 amp slo-blow fuse on the power cord of any radio with a transformer. The fuse will blow before the transformer can go into melt-down.
:
:
:
Pictures of your radio here:
http://www.radioatticarchives.com/radio.htm?radio=627

::Is the hum coming thru the speaker, or is the transformer vibrating so hard you can hear it?
::
::You could use the dim bulb test to determine if there is a short.
::A 100 watt light bulb is wired so that the bulb is on one leg of the power cord. Google 'dim bulb test'. This test tells you if excessive current is being drawn, indicating a short.
::
::Try this first with the tubes removed as suggested by Lewis.
::Do not leave the transformer powered up for any longer than necessary, as it could be on the verge of self-destruction.
::
::I recommend installing a 1 amp slo-blow fuse on the power cord of any radio with a transformer. The fuse will blow before the transformer can go into melt-down.
::
::
::
:Pictures of your radio here:
:http://www.radioatticarchives.com/radio.htm?radio=627
:
:: The hum is in the speaker. Radio receives great and plays with good volume. I will remove the tubes and do further checking.

:::Is the hum coming thru the speaker, or is the transformer vibrating so hard you can hear it?
:::
:::You could use the dim bulb test to determine if there is a short.
:::A 100 watt light bulb is wired so that the bulb is on one leg of the power cord. Google 'dim bulb test'. This test tells you if excessive current is being drawn, indicating a short.
:::
:::Try this first with the tubes removed as suggested by Lewis.
:::Do not leave the transformer powered up for any longer than necessary, as it could be on the verge of self-destruction.
:::
:::I recommend installing a 1 amp slo-blow fuse on the power cord of any radio with a transformer. The fuse will blow before the transformer can go into melt-down.
:::
:::
:::
::Pictures of your radio here:
::http://www.radioatticarchives.com/radio.htm?radio=627
::
::: The hum is in the speaker. Radio receives great and plays with good volume. I will remove the tubes and do further checking.
:I eliminated the electrolytic cap from the transformer lead to speaker terminal. The hum is gone and the transformer is running cool. Apparently, some previous repairs on the chassis were incorrect. Many thanks to everyone for their helpful input.

::I eliminated the electrolytic cap from the transformer lead to speaker terminal. The hum is gone and the transformer is running cool. Apparently, some previous repairs on the chassis were incorrect. Many thanks to everyone for their helpful input.
:
:

Thanks for the update, Chuck, and congrats on finding the screw up. Bungled repairs can be confusing to decipher sometimes, and you're lucky no permanent damage was done.
I still advise adding a fuse. If an inline fuse holder isn't handy, I will solder a couple of short leads directly to the fuse. Then solder one lead to the transformer terminal and the other to the power cord.

:::I eliminated the electrolytic cap from the transformer lead to speaker terminal. The hum is gone and the transformer is running cool. Apparently, some previous repairs on the chassis were incorrect. Many thanks to everyone for their helpful input.
::
::
:
:Thanks for the update, Chuck, and congrats on finding the screw up. Bungled repairs can be confusing to decipher sometimes, and you're lucky no permanent damage was done.
:I still advise adding a fuse. If an inline fuse holder isn't handy, I will solder a couple of short leads directly to the fuse. Then solder one lead to the transformer terminal and the other to the power cord.
:
:I played the radio today for about an hour, and although the hum is gone, the transformer got quite warm. Not too hot to touch, but not normal either. I guess I have more diagnostic work to do. I did add an inline fuse.