No sound from radio speaker, but can hear from headphone jack

[deoxit hufr]

Hello all,

new here so If I am doing something amiss... please advise

I just purchased a used radio that seems to have a blown internal speaker.. or some other component
that is rendering it inoperative.

Could someone suggest some trouble shooting steps when ( or before ) I pop this open?
I think I would be able to see if something has come loose, or something obvious like that,
but I'm expecting something a little more complicated to isolate...
and I'm new to attempting repairs so, many "obvious" things wrong.. would not be so obvious to me..

thanks in advance

deoxit hufr

 

[Bluejets]

Headphone jacks usually have a switching mechanism which isolates the main amp when headphones are in use.

Perhaps this switching mechanism is not returning the signal to the main amp after the headphones are removed.

 

[deoxit hufr]

Yes I had seen some info about this during my search.. this is a 3.5 mm jack..
what would be the recommended treatment for it? replace the jack? clean and try to release
the mechanism? I don't want to use the headphone jack anymore necessarily.. It's not really a portable
radio.. and just want the sound from the speaker, I could remove the headphone jack and not
be missing anything.

thanks for reply

 

[Bluejets]

1......First you need to be proficient with the use of a multimeter and some circuit tracing skill.
Without this you will be lost.
2......Next it would be necessary to determine if this is indeed where the fault lies.

3.... If it proves to be the case then bridging it out would suffice.
However, again you need tknow what you are doing.

 

[deoxit hufr]

you will be lost.

1. of course I'm lost.. hence why I am here..
2. would the multimeter be the only tool I need to determine this? ( and un-losting myself ofc)
3. I'll look into this .. "bridging it out" which I have no idea about your term as well

thanks for the analysis all the same.. but I did already know I am ignorant and incompetent

 

[shrtrnd]

There might be a problem with the speaker itself, but as Bluejets said, the headphone jack is usually the problem.
When you have no headphone plug installed in the jack, the jack wiring leaf spring supplies the signal to the radio speaker. When you insert the headphone plug, the leaf spring in the jack is moved to disconnect the signal to the radio speaker, and redirect it to the headphones.
Bluejets recommended what a tech would normally do to confirm the actual problem.
Without test gear, if you're trying to fix this (no guarantee without Bluejets advice), open the radio, look at the
headphone jack wiring, make sure a wire on it is not broken-off or somehow disconnected (which would explain
the problem), and look at where the leaf spring connection directs the wiring contacts when you insert the headphone jack. If you replace the jack, make SURE you buy the correct replacement jack. Some are mono, with two wiring connections, and some are stereo, with three wiring connections to the jack.
Any other specific questions about this, somebody here will help you.
Good luck with troubleshooting.

 

[deoxit hufr]

@shrtrnd

thank you sir.. some concrete steps to follow.. I do appreciate your time in answering..
and I will try this and report back here..

this is a small jack 3.5 mm, I suppose someone out there is actually selling them..
would RS carry ? or would I need to hunt them down online?

knowing some good outlets would be great.. as I have some other pieces of equipment
I want to try and give a 2nd act to.. instead of taking them to be recycled just yet.

thanks again...

 

[shrtrnd]

I don't know the electronic part stores in your area. They're probably available on-line, but I'd just check your local
phone book and find an electronic parts store, computer parts store, or similar entity.
The reason I suspect the jack itself first is your symptom and the fact that you bought it used.
The previous owner may have deliberately disabled (disconnected) the speaker, so that only the headphone jack
would work (Who knows, a loud teenaged kid maybe). Or he may have inserted a wrong-sized plug at some time
that bent a spring contact (I've seen a lot of those).
Frankly, if your headphone works fine, repair fault should be relatively easy to find and fix.