GF-777Z tuner adjustments - weak reception

[Cpl-Chronic]

Got a good score on eBay, snapped up my first GF-777Z & the tuner is out of alignment or damaged. I barely get any stations in & stereo is but a flicker on the strongest stations. I've heard there is a pot or screw to adjut to bring it back into alignment or something. Below is a pic of the tuenr board which will get a good blast of switch cleaner to clean it up, this afternoon. I'm hoping someone can tell me what to adjust & how to do it in somehwat straight forward language. I don't have an oscilliscope so I ahve to do this by ear. Anyone have any suggestions?

If you can look at the photo below & point me to the pot(s) or screw(s) to play with & what to watch out for, I'd really appreciate it.

http://i48.tinypic.com/fasshc.jpg

 

[baddboybill]

Check your antenna connection on board and actual antenna. You can also turn tuner back and forth down dial a few times. This may clear up tuner.


Sent from my iPhone using Tapatalk

 

[Cpl-Chronic]

well, used contact cleaner to spray down the switches & tuner board, etc. but the tuner is still out of whack. I need to know which pot to adjust to bring it back to life. It appears to be working OK as I do get some stations in but not clear at all. The Line-In switch & balance came back to life, the volume isn't as scratchy & now I'm playing some beat-box classics through my CD palyer & it sounds good overall. The left outer woofer is crackly & the tweeter on the left doesn't work at all yet. It may be the crossover cap affecting both as the drivers are wired in paralell. The super woofers are in perfect shape & acually sound pretty good.

 

[Superduper]

You might be able to get the 19khz pilot signal adjustment back into alignment by ear and lacking a manual, you can find the pot nearest the mpx decoder chip, which is probably the pot you need to adjust. This will not improve reception signal strength, however.

NOTE... YOU SIMPLY CAN NOT do a tuner alignment by "ear." If you go that direction and indiscrimiately start turning the pots, you will almost surely throw the tuner out of wack to the point that it might not be able to be brought back. You need equipment to do a proper alignment. This simply isn't an adjustment you can do without the proper equipment. These will include:

FM stereo signal generator.
oscilloscope.
Marker generator (or an included feature in the FM signal generator).
Millivolt Meter.

Also, while a tuner can drift out of alignment over time and could benefit from a tuner "re-alignment," it should be noted that when a tuner drifts off, it could also be caused by weakening RF amps, the result of which if uncorrected, no amount of tuner realignment will fix.

 

[superlew]

Good advice, Superduper.

That's why I don't really play around with tuners other than a cleaning.

Like I said in a previous post, I learned the hard way.

 

[Cpl-Chronic]

Thanx for the heads up Superduper. A couple of posts allluded to the possibility to make an adjustment to bring the tuner back in line. I'll look into it further before doing anything rash. I can definitely live with using lin-in for now & both tape decks seem to be working OK.

 

[goodman]

with Superduper. tuner alignment is not easy job.
In service manual is detailed info how to do alignment. Of course, additional devices are needed.
I recommend you, take boombox to a specialized service to resolve this problem.