GEC valve radio BC5...
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[Closed] GEC valve radio BC5839 volume fades after a while

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Posts: 16910

This is a lovely radio and works almost perfectly except after a while the volume suddenly drops low. Can anyone help me please?  Also what does X79 valve do?

Topic starter Posted : 12/02/2020 11:55 am
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Famed V-Ratter Registered
Posts: 4934

Hello there and welcome to the forum.

The X79 is a frequency changer and is used at the front end of the radio.

As for the fault, you maybe could try to narrow it down a little as to what area of the set it lies. For example, you could feed in an external audio source into the Gram input to check the audio stages of the set. A CD player could be used for example. If all is well, then the fault is further back.

Has the radio ever been serviced recently? For example have any defective capacitors been replaced? If not, it could be an electrically leaky capacitor (or several) reducing the gain of the set. It could also be a faulty valve, the X79 a possibility. The fault may even lie outside of the radio if the aerial is defective in some way, like a loose connection.

The list of possibilities can be quite long.... a case of elimination one by one is needed.

Posted : 12/02/2020 12:29 pm
Vrat Founder Admin
Posts: 11262

Hi and welcome to the forum. ? 

I suspect from your query you might be a keen novice? Apologies if I'm way off.

Can we therefore establish if the above is true or false, and ask the following:-

  1. What is your experience with vintage valve circuits?
  2. Do you have a circuit diagram and can you understand one?
  3. Do you have a multimeter and know how to take readings with regard to resistance and voltage checks?


Knowing all the above will help members correctly pitch their assistance, to match your level of experience.  This information will also help folk keep you safe if you are indeed a novice. Without knowing any of this there's a possibility of blinding you with science if you are new, a risk of putting you in danger if you're not aware of the voltages involved. Also, If you are experienced giving you an unnecessary egg sucking exercise.

If you are new to this great hobby you might find this useful reading:

Posted : 12/02/2020 12:54 pm
Vrat Founder Admin
Posts: 11262

Thread closed

OP registered almost 4 weeks ago, posted his query and has not logged in since. Questions asked by OP received responses, but they have made zero follow up. It can always be opened again should the OP turn up.

Posted : 05/03/2020 11:44 am