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RCA problem
6/2/2003 1:19:08 PMRob
Hello

I am not sure if this site is for my system but here it goes. I have a big mid 60's RCA Soild state cabinet stereo Model ST-14. I bought it for kicks and it works fine. The problem is that when the power is on there is a very noticable low hum through the speakers, even when nothing has been selected (ie radio , phono etc). Volume has no effect on the hum.

Has anyone any ideas? I am OK with electronics but I need a little help. I would assume it was something to do with the power supply or amp.

Any help would be appreciated
Thanks
Rob

6/2/2003 2:29:17 PMNorm Leal
Hi Rob

Most likely electrolytic filter caps. These dry out over time and allow hum.

Another thing that can cause hum is open inputs on an amplifier.

Norm

:Hello
:
:I am not sure if this site is for my system but here it goes. I have a big mid 60's RCA Soild state cabinet stereo Model ST-14. I bought it for kicks and it works fine. The problem is that when the power is on there is a very noticable low hum through the speakers, even when nothing has been selected (ie radio , phono etc). Volume has no effect on the hum.
:
:Has anyone any ideas? I am OK with electronics but I need a little help. I would assume it was something to do with the power supply or amp.
:
:Any help would be appreciated
:Thanks
:Rob

6/4/2003 11:19:30 AMrob
:Hello Norm
Thanks for the fast reply. There are two electrolytic caps on the transformer/amplifier unit. They are big 2.5" long and 1" in Dia. Could these be the filters? They are the only ones visible there.

They are
#B 124536-10
MesseyUK
CE 1584/14
2500uf 25v DC WKG
Oct 65

Thanks
Rob Guy


Hi Rob
:
: Most likely electrolytic filter caps. These dry out over time and allow hum.
:
: Another thing that can cause hum is open inputs on an amplifier.
:
:Norm
:
::Hello
::
::I am not sure if this site is for my system but here it goes. I have a big mid 60's RCA Soild state cabinet stereo Model ST-14. I bought it for kicks and it works fine. The problem is that when the power is on there is a very noticable low hum through the speakers, even when nothing has been selected (ie radio , phono etc). Volume has no effect on the hum.
::
::Has anyone any ideas? I am OK with electronics but I need a little help. I would assume it was something to do with the power supply or amp.
::
::Any help would be appreciated
::Thanks
::Rob

6/4/2003 11:49:27 AMNorm Leal
Hi Rob

The 2500uf @ 25 volts would be filter caps. They were made in 1965 and may have dried out causing hum.

Norm

::Hello Norm
:Thanks for the fast reply. There are two electrolytic caps on the transformer/amplifier unit. They are big 2.5" long and 1" in Dia. Could these be the filters? They are the only ones visible there.
:
:They are
:#B 124536-10
:MesseyUK
:CE 1584/14
:2500uf 25v DC WKG
:Oct 65
:
:Thanks
:Rob Guy
:
:
:Hi Rob
::
:: Most likely electrolytic filter caps. These dry out over time and allow hum.
::
:: Another thing that can cause hum is open inputs on an amplifier.
::
::Norm
::
:::Hello
:::
:::I am not sure if this site is for my system but here it goes. I have a big mid 60's RCA Soild state cabinet stereo Model ST-14. I bought it for kicks and it works fine. The problem is that when the power is on there is a very noticable low hum through the speakers, even when nothing has been selected (ie radio , phono etc). Volume has no effect on the hum.
:::
:::Has anyone any ideas? I am OK with electronics but I need a little help. I would assume it was something to do with the power supply or amp.
:::
:::Any help would be appreciated
:::Thanks
:::Rob



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