gf777 Mid speakers issues

pimpkie

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May 12, 2017
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hi everyone ..i finally fix my potties and everything is fine except one thing

i notice that olny one of my two bass speaker works ( L)
so the ® one doesn't work at all ...i also notice that when i plug the R bass speakers on the L one ... the R speaker works so the issue doesn't come from the speakers... i figure that the bass works when this wires (2 purple 1 blue and 1 grey) are plugged... so i changed the wires but the problem is still the same ...i don't know where this issue come from (capacitor ? knob? or some thing else) i really need your help so please can somebody tells me how to proceed to fix this?

thank you very much so far you guys!!!!!

Bonjour tout le monde .. j'ai finalement réparer mes potards et tout va bien sauf une chose

Je remarque que l'un de mes deux haut-parleurs fonctionne ( L)
Donc, le ® ne fonctionne pas du tout ... Je remarque également que lorsque je branche les haut-parleurs R sur le L ... le haut-parleur R fonctionne donc le problème ne provient pas des haut-parleurs ... J'ai remarqué aussi que la basse fonctionne lorsque ces fils (2 violets 1 bleu et 1 gris) sont branchés ... alors j'ai changé ces fils mais toujours le même problème Je n'sais pas d'ou cela peut provenir ...? Bouton potards condos? Ou quelque chose d'autre), j'ai vraiment besoin de votre aide, donc quelqu'un pourrait me dire comment procéder?
merci a tous !!!!!!!!!!
 

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BoomboxLover48

Member (SA)
Dec 3, 2010
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I had the same issue with one of my Sharp 777.

I can see your black/white and yellow connector is not plugged in. That is the top connector.

After trying so many things I finally replaced the whole amplifier assembly with the board where you connect the plugs. That solved the problem.
 

pimpkie

Member (SA)
May 12, 2017
27
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39
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BoomboxLover48 said:
I had the same issue with one of my Sharp 777.

I can see your black/white and yellow connector is not plugged in. That is the top connector.

After trying so many things I finally replaced the whole amplifier assembly with the board where you connect the plugs. That solved the problem.
yes indeed the b/w yellow is not plugged for testing the bass olny speakers .....anyway thanks i guess i have no choices but to do that too... there's a capacitor or something in that amp board that sould be down or used... if you have any advices that could be cool for me thank you my friend
 

BoomboxLover48

Member (SA)
Dec 3, 2010
5,738
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Chicago, IL
BoomboxLover48 said:
This is the part you need to replace.
It is pretty hard to pin point to a component on that board. It could be an issue with the IC also. The best option is to replace the whole section. This is the part you need to replace.

I've worked on GF777 a lot and was so easy to replace it. ~ Royce
 

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pimpkie

Member (SA)
May 12, 2017
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BoomboxLover48 said:
This is the part you need to replace.
It is pretty hard to pin point to a component on that board. It could be an issue with the IC also. The best option is to replace the whole section. This is the part you need to replace.

I've worked on GF777 a lot and was so easy to replace it. ~ Royce
hi there royce thanks for the advice... i want you to look at this i have a second part i picked up on a other boombox but there 's a metal plate missing and the "beat cancel swicth" is broken so tell me if this plate is important to get the boombox working and what the beat cancel button is for ? also i managed to get a set of grills but the corner locks are missing on each grills and i don't know the english for those plastic corner "dicks" and where to buy it , i need 4 of them!!!!

please try to take a look and tell me everything you know about it .... merci mon ami ^^
 

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pimpkie

Member (SA)
May 12, 2017
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riker1068 said:
From your pic, you're missing one of the amp chip's and it's heat sink!!
IMG_4175.PNG
If bought this way, someone took that out.
it's useless to replace with that part ok....do you have any ideas if it's a capacitor or something else to change to make my mid speakers work again? the first one i have is in good shape but olny one of the two speakers is working and i don't know where the problem is located ?
 

nikonfoo

Member (SA)
Jan 27, 2015
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you are missing an important part amp chip and heat sink
never seen someone take out all that and just stop
Glade to see you are getting closer to the problem
Grill corners is the name i would give them unfortunately they will be hard to find
 

pimpkie

Member (SA)
May 12, 2017
27
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france
nikonfoo said:
you are missing an important part amp chip and heat sink
never seen someone take out all that and just stop
Glade to see you are getting closer to the problem
Grill corners is the name i would give them unfortunately they will be hard to find
thank you so much i appreciate .... as you can see i managed to get another complete but in bad shape 777 boombox
so i did fix all potties, tweeters, a set of speakers, knobs cover and a cassette player but its amp part has been already taken apart and apparently i need this part to change so i'm getting closer i hope so if you have any advices i would gladely listen what i have to say about it

also i'm not quite sure but i had to solder this wire because of its solder was bad ...could it be a problem i don't know what those wires are used for ? it's near the tuner section
 

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frox

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Mar 15, 2017
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try to replace all capacitors near power amps chip .verify fader / bass and superwoofer bass poties
 

pimpkie

Member (SA)
May 12, 2017
27
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39
france
frox said:
try to replace all capacitors near power amps chip .verify fader / bass and superwoofer bass poties
ok thanks ...tell me which capacitors do i have to change ... where and which one exactly?
look at the photo and try to tell me please... this is my second part where i will take away all capacitors that i need
Ok merci ... dis-moi quels condensateurs dois-je changer ... où et lequel exactement?
i changed all poties, cleaned them one by one so i guess it's from the amp part but i dunno which one to change
 

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frox

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Mar 15, 2017
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your power amp card miss ic802 power amp mosfet
change 3300uf capacitor and 1000uf capacitor and the rust capacitor at the bottom of your pic