Deck 1 slightly lower volume (GF-767)

[ElectroKid]

Hi all,

Deck 2 sounds great and with crisp high volume while deck 1 is a bit muffled.
Playing deck 1, the VU meter needle does not reach the same level as deck 2.
The issue is in both channels (L & R) so I must be looking for some common IC like the 54512L or the 51301P...
Maybe the head has deteriorated with time but I would not dare touch it yet as it is delicate messing with its screws...
Also has anyone a better copy of this model service manual 767 Z as mine is for H or E and is too blurry.
Thanks.

 

[baddboybill]

Clean, demagnetize and adjust azimuth first on head


Bad Boy Bill

 

[ElectroKid]

head cleaned with alcohol - same result.
is there a makeshift device tutorial I can build as tape demagnetizer as I cannot get a hold on one (should ask a local repairer...)
also this tape plays the way it plays after I give it a slight tilt to one side making it sit slightly off inside the deck... is this a sign of azimuth issue? nevertheless it play a bit better but still ~3dB lower compared to deck 2

 

[baddboybill]

eBay has demagnatizers. And I guarantee if you do this it will improve sound. The azimuth adjustment is the tiny Philips screw on head adjustment. You can adjust while tape is playing to get best overall sound quality. Use a tiny demagnatized screwdriver as well


Bad Boy Bill

 

[ElectroKid]

OK, so I plan to close the unit after some resto work...
I assume demag can be done when radio is assembled but will the azimuth screws be accessible or should I leave it open on the bench... thanks a bunch

 

[baddboybill]

You can demagnetize and set azimuth while unit closed. There will be a tiny hole at bottom of deck door to put tiny screwdriver in while you are playing cassette tape or even better door pops off easily on these for better access


Bad Boy Bill

 

[Cpl-Chronic]

You can demagnetize and set azimuth while unit closed. There will be a tiny hole at bottom of deck door to put tiny screwdriver in while you are playing cassette tape or even better door pops off easily on these for better access Bad Boy Bill

Be careful when trying to remove the cassette doors. You actually have to push in on the tabs that hold the cassette door in place & swing down but if you don't do it right, you could crack the tabs, etc. Better to adjust the azimuth without removing the doors. You can do this 95% of the way by ear but you need a good quality recording that has a lot of mid & highs which you are very familiar with to judge by ear when the head is properly aligned. You do need a Philips(star) head jeweler's screwdriver to adjust the alignment screw. I really doubt any IC's are the issue.

Cpl

 

[Cpl-Chronic]

There may also be a surface mount pot on the cassette circuit to adjust gain for the 2nd deck. I'm not familiar with the 767 or 777 circuitry but that may very well be possible so that the decks can be adjusted at the factory to match gain strength between the 2.