HELP WANTED ! Sharp GF-555. NO voice / sound on left speaker ??? Right one works

[Kris]

Hi there! I have an issue on my Sharp GF-555 boombox. The right speaker works as a charm (and also bass & treble works), but does not give any sound from the left speaker ? Right / Left slider don´t make difference, only sound goes mute if i turn slider totally left (only very very low volume can be heard) On the attached picture you can see the board where are 3 pins (+ 1 pin further left) total 4 pins, where this white speaker adaptor goes into. I have tried to put the adaptor also vice versa, leaving the further left pin out and then the left speaker works normally (with bass & treble also) ?? So, this way i know that both speakers do work. Any ideas how i may tackle on this one ???? All help is appreciated
Ps: Cassette decks do work and sound comes, from right or (left), depending on how the speaker adaptor is put..

-Kris-

 

[hopey]

Try pressing Play & Rec 30 times, also plugin /out headphones 30 times.

 

[Kris]

Thanks Hopey, u gave me hope, but sadly that tip didn´t work. I tried it couple of times, no result I ´ve also cleaned the balance slider thoroughly, so i would say that bad slider is out of the question... Maybe a bad capacitor ? or something like that , either way, i´m clueless on this one

 

[hopey]

Could be the Headphone jack it isolates the speaker output.

 

[Kris]

Maybe But, how to be 100% right...that´s a good question. Any idea how i could be sure, that it´s not the case, meaning how to rule this option out ?
I did try the first plugin / out thing again couple of times, with no result. I put a few pictures along of the headphone jack...

 

[hopey]

you need the service manual to get the pin out for the ground (Normally Headphone switches the Neg on each speaker and shunts a resistor in series to create a voltage drop R704, R705). There is another way to check just ground (-Neg) the speaker not working.

 

[Tinman]

Are both sides of the headphones working when plugged in?
That could tell you if the problem is before or after the jack.

 

[Kris]

Are both sides of the headphones working when plugged in?
That could tell you if the problem is before or after the jack.

No, only the right speaker of the headphones work, when plugged in, so same thing no matter if the headphones are connected or not, left one just doesn´t work.
Should i take those resistors (R704, R705) off the board to check them ? Or can u check these resistors while they are still connected on the board ? Or maybe look for a capacitor, that´s gone bad ?

 

[hopey]

It's sounding like the volume pot.

 

[Tinman]

It's sounding like the volume pot.

I agree.
I've had wipers fall out of volume pots that caused a constant volume on one side.
You can check out my last volume pot problem here.
https://boomboxery.com/forum/threads/ge-volume-potentiometer.31794/

 

[hopey]

It would be worth re-flowing the solder on the PCB at the Headphone Pins and The Speaker out connection.

 

[Kris]

It would be worth re-flowing the solder on the PCB at the Headphone Pins and The Speaker out connection.

Thanks for the advice. So you say i should first take the headphone jack off and then re-solder it back on, on the Pcb (all 7 pins) ?? I might try that, i have nothing to lose...
It is odd, i can clearly hear a "hiss" (when it´s on and stand by, but not listening radio or cassettes) coming from the left speaker at all times, but, just no sound..
By the way, could this volume slider potentiometer (not round, like they usually are) be somehow so "stucked" / broken, that it won´t play the left channel / speaker ?
I don´t know..but, i do know, it slides effortlessly, and because i have cleaned the volume-slider very well already, makes me think the issue is not on that...
How often this kind of a problem is due to a broken capacitor or resistor ??

 

[hopey]

Thanks for the advice. So you say i should first take the headphone jack off and then re-solder it back on, on the Pcb (all 7 pins) ?? I might try that, i have nothing to lose...
It is odd, i can clearly hear a "hiss" (when it´s on and stand by, but not listening radio or cassettes) coming from the left speaker at all times, but, just no sound..
By the way, could this volume slider potentiometer (not round, like they usually are) be somehow so "stucked" / broken, that it won´t play the left channel / speaker ?
I don´t know..but, i do know, it slides effortlessly, and because i have cleaned the volume-slider very well already, makes me think the issue is not on that...
How often this kind of a problem is due to a broken capacitor or resistor ??

Every box is different there is no simple answer it's just a process of patients and elimination. You don't need to remove the headphone jack just heat the solder up with a soldering iron and feed a bit more solder in, same on the speaker connection pins. Less likely to be a resistor could be a cap.

 

[Radio raheem]

I would also check the amp chip it may have failed but you would need superduper or hopey to help you with that....

 

[Wes125]

clean all these switches with spray. and do the record bar thats the most importent thing as a lot of radio cassettes run the audio through these.. remove all plugs on circuit boards and clean contacts as the aluminum goes black and loses contact. spray cleaner in plug holes before u push em back on...ive done loads of stereos with these push in plugs and they are a pain in the arse. they always need cleaning. as from this pic i have the same unit and mine kept cutting out on one channel..so give all this ago before u start messing with chips