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Issues with my GF777...

isolator42 - 2008-12-01 03:28

Here's the story of how I came to own it.
Issues...
Let's see now:

- from all sources, the highs & mids sound balanced using the speakers, but there is less bass from the left channel. This applies to both the outer & inner speakers
- both left speakers have less cone movement, but it's more obvious with the middle ones, of course. Headphones sound just fine, so it's something to do with the power amp circuitry.
I want to fix this but I don't have a clue, & I'm hoping a good clean inside might help things.

- tape fader not working properly: it leaves some sound in the left channel from the faded out deck.
I would like to attempt fixing this but unless switch cleaner sorts it out, I haven't a clue.

- decks both play, but ffwd & rewind dying on both
belts? Idler wheels? I shall investigate. Bit more confident here...

- rear casework repaired & only 4 screws holding it together
Not ideal, but maybe something I can improve upon. It doesn't rattle at higher volumes. Loud, aren't they? Smile If anyone is parting out one of these I'll pay for the rear case!

- bars missing from the outer speakers.
I don't mind, really. It looks fine with the grilles on. I'll tidy up the bits left from their removal, though. Wonder why someone did that?


I have the service manual & a users guide for the GF777, so as soon as I dare to take this thing home, I can get cracking with the fixes... Smile

jvc.floyd - 2008-12-01 06:46

hi i can tell you the volume difference from left to right is normal for the gf777 as well as the difference in cone movement .you can even it out using the super woofer knobs on the middle sprakers but not much you can do with the outer ones to balance the sound.

fatdog - 2008-12-01 08:49

I had issues with the bass also. It turned out to be a dirty BASS pot. I would imagine that the fader issue is also a dirty pot.

Here's a link to download the write-up I did on changing out belts and fixing the FF and REW for the GF-777:

http://www.mediafire.com/?7zmrmzm9jrl

isolator42 - 2008-12-01 15:10

Bobby, that manual is great, thanks Smile

I hope you're right about the dirty pots...

fatdog - 2008-12-01 15:49

Good luck with the repair. Let us know how it goes, too! Nod Yes

happy - 2008-12-01 16:06

Sounds like a good clean on all controls and if problem is still there and works fine on h/phones then it can only be the ext speaker sockets main tarnished, as after h/phones the signal passes through these and then to the speakers also the subwoofers amplifier input signal is taken from the speaker output of the main outer channels reduced via a 56k resistor r817/818.
hope this helps.

isolator42 - 2008-12-02 06:05

quote:
Originally posted by Fatdog:
...Let us know how it goes, too! Nod Yes
...like I ever shut up about stuff like this Smile

Thanks again for the info.
Biggest problem is I need to do the work at home & this one is going to take some fast talking when it goes through the front door...

fatdog - 2008-12-02 15:12

Been there, done that!

Ask Freddie. Laugh Out Loud

oldskool69 - 2008-12-02 16:49

quote:
Originally posted by isolator42:
Biggest problem is I need to do the work at home & this one is going to take some fast talking when it goes through the front door...


Bobby (Fatdog) is spot on! I've witnessed and had to do the same! Laugh Out Loud

johnnygto - 2008-12-04 21:32

If it was a "very" noticeable difference.. mine was actually the input selector switch.. no kidding! I cleaned and moved it a little and both channels played the same... thought it was the balance control... nope.. input selector!! It also made the VU's work correctly! Confused

I still have to take my 777 apart and clean it better. Smile

Good luck with your repairs.

Johnny