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GF 777 Play button hold stuck and speakers smelling hot (burn)?

GF 777 777 777 speakers 777 play button sharp gf 777

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#1 pimpkie

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Posted 23 August 2017 - 12:44 PM

hi ... i have again another problem with my gf 777 ... i've been recently changed the amp part because i had speakers problems.

after i changed the part everything worked not 100% effective but enough to hear music from and i pod and i notice that the cassette deck was working too (A) plays on both speakers (B) only the right ones so there 's the issues begin i dunno why only the right side speakers working but my broblems didn't stop there.

 

after set everything complete i tried to test it again this time the tuner doesn't want to work so i switched to the cassette, the play button were stuck and press the stop button didn't change anything 

i did can hear the tape motor turning but there's nothing i could do to stop that damn "play" button, what happened next is i touched the right end speaker it was hot and the batteries i put inside too. where that OVERHEAT come from ? i have two 777 so i changed the power plug part but still the same .I did everything i could so far with all your precious help but i can't do anymore without your help once again PLEASE help me. 

THANKS TO ALL OF YOU !!!!!



#2 Superduper

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Posted 23 August 2017 - 09:28 PM

If your batteries are hot, you have a DEAD SHORT! If the speaker is hot, it is either now toast, or your amplifier is oscillating big time or putting out excessive DC. Also if you have a dead short, now voltage has completely sagged below operational threshold so it's no wonder that tuner doesn't work and that cassette stop solenoid isn't functioning. Either you've connected something wrong, or parts are bad.

I didn't participate in your threads before because all the talk of just swapping out parts is in my opinion, the wrong approach and not something I wanted to partake in. How can one look at a picture and tell you what part to change to fix something? Fixing an electronic device like this takes diagnostic work that involves measurements, tools and instrumentation is not optional, and some electronic knowledge to interpret the readings. It takes a logical approach, not just buying up all these scarce parts and throwing them at the boombox shotgun style. Taking a grail like this and applying shade tree tech is a shame. It really should have just gone to a repair shop to begin with. Anyone taking the time to study the circuit diagram will understand that this is not a learning project. Frankly, at this time, I wonder if more and possibly irreparable harm has been added.

So that being said, other than the first paragraph above, I have no further suggestions for you except maybe to seek some professional help. Not that I don't want to be helpful, however, I honestly feel the solution is beyond your ability to repair other than to just swap the whole boombox.

#3 pimpkie

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Posted 24 August 2017 - 05:24 AM

If your batteries are hot, you have a DEAD SHORT! If the speaker is hot, it is either now toast, or your amplifier is oscillating big time or putting out excessive DC. Also if you have a dead short, now voltage has completely sagged below operational threshold so it's no wonder that tuner doesn't work and that cassette stop solenoid isn't functioning. Either you've connected something wrong, or parts are bad.

I didn't participate in your threads before because all the talk of just swapping out parts is in my opinion, the wrong approach and not something I wanted to partake in. How can one look at a picture and tell you what part to change to fix something? Fixing an electronic device like this takes diagnostic work that involves measurements, tools and instrumentation is not optional, and some electronic knowledge to interpret the readings. It takes a logical approach, not just buying up all these scarce parts and throwing them at the boombox shotgun style. Taking a grail like this and applying shade tree tech is a shame. It really should have just gone to a repair shop to begin with. Anyone taking the time to study the circuit diagram will understand that this is not a learning project. Frankly, at this time, I wonder if more and possibly irreparable harm has been added.

So that being said, other than the first paragraph above, I have no further suggestions for you except maybe to seek some professional help. Not that I don't want to be helpful, however, I honestly feel the solution is beyond your ability to repair other than to just swap the whole boombox.

yeah... i understand the fact that a newbie like me trying to fix that beauty without the knowledge can piss you off...but frankly my intentions aren't bad at all ..i think this device is a great piece of history and what a beauty this thing could be... to make things short i recently get a amp part from japan (gf 919) from "nickonfoo" or the thing is that i have a 777 ! so i guess the problem come from this part either because of the volt difference  (100v japan / 220v europe) or the part has already some problems.either way i'm screwed ....thanks anyway to took the time to explain ! 

 

one last thing what's the "beat cancel" switch is used for? it has 3 positions A B C i dunno what's is for... when i tried to push the switch the plastic piece broke so 



#4 Superduper

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Posted 24 August 2017 - 07:51 AM

#1) beat cancel typically changes the bias oscillator frequency (during recording) in case there is interference with the radio

#2) all of these gf series whether Japan, North America, Europe all work at the same voltages internally. The voltage differences pertain to the power supply which drops the voltage from the local mains to the same 15v amount. Bottom line is that voltage has nothing to do with it. There can, however be other differences between regional parts in terms of features but typically speaking, they wouldn't then be drop in replacements since there will usually be interface differences as well.

#5 pimpkie

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Posted 24 August 2017 - 08:20 AM

#1) beat cancel typically changes the bias oscillator frequency (during recording) in case there is interference with the radio

#2) all of these gf series whether Japan, North America, Europe all work at the same voltages internally. The voltage differences pertain to the power supply which drops the voltage from the local mains to the same 15v amount. Bottom line is that voltage has nothing to do with it. There can, however be other differences between regional parts in terms of features but typically speaking, they wouldn't then be drop in replacements since there will usually be interface differences as well.

ok then... the problems came after i chaged this part .... imma leave this and try to contact a pro and hope for the best 

thanks a lot have a nice day





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