hello. have a transoceanic A500 i belive. any way it has a ac hum on am band. all the bands work fine. replaced all the electrolytic caps. now hum is worse and lost some of my am. short wave works good with no hum. thank you

Hi:

Start by checking the tubes out on a good tube tester. You could have a heater to cathode short in one of them that could cause the hum. A good tester will show this.

Lou

:hello. have a transoceanic A500 i belive. any way it has a ac hum on am band. all the bands work fine. replaced all the electrolytic caps. now hum is worse and lost some of my am. short wave works good with no hum. thank you
:

:hello. have a transoceanic A500 i belive. any way it has a ac hum on am band. all the bands work fine. replaced all the electrolytic caps. now hum is worse and lost some of my am. short wave works good with no hum. thank you
:
sorry its an H 500

Paul

Broadcast & short wave use the same circuitry. Only coils and band switch are different. Do you have bad band switch contacts? Antenna coil connected?

Here is info on H500:

http://www.transoceanic.nostalgiaair.org/h-500.htm

Norm

::hello. have a transoceanic A500 i belive. any way it has a ac hum on am band. all the bands work fine. replaced all the electrolytic caps. now hum is worse and lost some of my am. short wave works good with no hum. thank you
::
:sorry its an H 500
:

well the am band is the only one that has the hum. short wave bands work loud and clear. deoxit on the band switch. the radio had this hum before i did anything. if i diconnect the am antenna the hum goes away. going to try recapping the rest of the set.

:well the am band is the only one that has the hum. short wave bands work loud and clear. deoxit on the band switch. the radio had this hum before i did anything. if i diconnect the am antenna the hum goes away. going to try recapping the rest of the set.
:
p.s. replaced all the tubes from a working set and it still does the same thing.

Paul

If the bandswitch for broadcast doesn't close leaving a contact float may cause hum?

Does it sound like 60 cycle hum? Could it be outside interference from some nearby electrical device? Circuits are the same for short wave and broadcast bands except coils and switching.

::well the am band is the only one that has the hum. short wave bands work loud and clear. deoxit on the band switch. the radio had this hum before i did anything. if i diconnect the am antenna the hum goes away. going to try recapping the rest of the set.
::
:p.s. replaced all the tubes from a working set and it still does the same thing.
:

hi. ive allready thought of that norm. thank you. tried my other zenith transoceanic in the same place on the same ac circut. no hum on them. also just got done recapping the rest of the radio. found a few resistors that went weird. still hums on am. but when i pulled the antenna of the cover a note fell out. dated june 1959, said that radio works fine but has a low hum on am.unable to repaire. thank you for your help
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hello again. well after recapping my transoceanic A600 the darn thing had an awfull hum on am. i said oh great now what. after tearing my hair out i tried the old lets turn the plug around. man what a difference that made. so the other radio has an old poleried plug on it. replaced that but changed the order of the two wire now the H500 works and sounds perfect. thank you everyone for your help.
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:hello again. well after recapping my transoceanic A600 the darn thing had an awfull hum on am. i said oh great now what. after tearing my hair out i tried the old lets turn the plug around. man what a difference that made. so the other radio has an old poleried plug on it. replaced that but changed the order of the two wire now the H500 works and sounds perfect. thank you everyone for your help.
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Congradulations Paul,
Looks like you topped that guy from 1959!

All the Best,

Bill