Lubed & Oiled the GF-9191X-Still Weak Motor!

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Ghettoboom767

Ghettoboom767

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Hi everyone-I just got into the GF-9191X today.The tape is slow and the power on the tape deck is not near as powerful as the radio.
The radio on all bands works perfect.
The tape deck motor was oiled today but it seemed crusty and the date on the notos is like March 1980'-old!
My speed is little better but I firmly believe it needs a new motor.
I lubed all shafts and pulleys and tape engagements.
I really like this boombox as it is very clean BUT it needs a new motor and does anyone have a clue as why this is onlty about 1/2 as powerful in tape deck?
On radio it cranks.
Also-one other issue since I've had it.
The stereo wide is alomost normal on both sides but right side not as poweful.
The left side is always normal in strength.
But in regular stereo mod eth eright side is almost silent-very,very weak.But on mono normal on both sides.
Any suggestions.
Thanks & have a great weekend-GB. :hmmm: :choco: :-)


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Superduper

Superduper

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If the tape strength is not as strong, check to make sure the tape head depth is correct. If too shallow, then the signal strength will be low. It's also possible that the tape equalization amp is weak although if both left/right is the same, it's more likely that the tape heads are too shallow.

Weak motor: Maybe try removing this motor and drop it into a cup of water while it is running (hook up to 9v battery) -- really, no kidding. After a few minutes, the water wil probably turn black. After the motor dries, you can then lube it and see if performance improves. Either that or just try standard cleaning solutions.

MONO mode: The left and right signal is combined together and fed to both amplifiers.
Stereo Mode: Left and right circuits are independant and seperate
Wide Mode: As in Stereo except opposite signal runs through a delay circuitry and the out of phase signal is mixed into the other channel.

The reason you are hearing normal signal in mono is because 1 side is dead and the single channel is fed to both amps.

In stereo, because right channel is dead, that is why 1 side is normal, the other is silent.

In wide mode, one wide will be normal. The other side (that is dead) is being fed an attenuated out of phase signal from the opposite channel. That's why 1 side sounds normal and the other side sounds weak.

In short, you have 1 dead channel BEFORE the main amp. This could be a broken circuit, it could be a failed preamp on the right channel. Also, it could be the volume, bass or treble controls worn out (broken connection) in the control itself. Sorry, but the testing part of this is gonna be on you.
 
Ghettoboom767

Ghettoboom767

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May 6, 2009
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Superduper said:
If the tape strength is not as strong, check to make sure the tape head depth is correct. If too shallow, then the signal strength will be low. It's also possible that the tape equalization amp is weak although if both left/right is the same, it's more likely that the tape heads are too shallow.

Weak motor: Maybe try removing this motor and drop it into a cup of water while it is running (hook up to 9v battery) -- really, no kidding. After a few minutes, the water wil probably turn black. After the motor dries, you can then lube it and see if performance improves. Either that or just try standard cleaning solutions.

MONO mode: The left and right signal is combined together and fed to both amplifiers.
Stereo Mode: Left and right circuits are independant and seperate
Wide Mode: As in Stereo except opposite signal runs through a delay circuitry and the out of phase signal is mixed into the other channel.

The reason you are hearing normal signal in mono is because 1 side is dead and the single channel is fed to both amps.

In stereo, because right channel is dead, that is why 1 side is normal, the other is silent.

In wide mode, one wide will be normal. The other side (that is dead) is being fed an attenuated out of phase signal from the opposite channel. That's why 1 side sounds normal and the other side sounds weak.

In short, you have 1 dead channel BEFORE the main amp. This could be a broken circuit, it could be a failed preamp on the right channel. Also, it could be the volume, bass or treble controls worn out (broken connection) in the control itself. Sorry, but the testing part of this is gonna be on you.
Click to expand...

Norm-Thank-you!
I had a sneaky suspicion that the right channel is dead because of the stereo wide mode it uses some of the left channel like you said.
I'll have to get somebody with some testing equipment in on this one or just have it fixed on of these days.Like I said this is one of a couple of boomers that need further assistance than what I have for equipment for testing.
This is a really nice looking box so it will be worth it to get it going.
I will try that on the motor-I heard that once before here.What kind of oil do you suggest?
Machine oil but what kind or just 3 in 1 or what's good? That's easily available?
I don't have anything to lose-this motor has spun a little in it's life-I can tell. :-O
At least it's somewhat close to speed-better than before-Wish it had a speed adjustment like that M-50!
Have a great Sunday-GB. :-) :yes:
 
Superduper

Superduper

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You should also check and verify that the belts are correct and that there is no binding on any of the other parts -- they will have an effect. If the belts are shorter or thicker than normal, it puts a bigger strain on all the parts. Also, sometimes, even the tape counter could affect things if it's kind of cruddy and sucking up the power from friction.

Finally, are you sure the problem is the motor itself and not the transport mechanism? Sometimes, slight slippage can't really be detected because everything is spinning but the slight slippage can cause slightly slower than normal playback. I treat all the pulleys with rosin anti-slip coating and it really helps to cut down on belt slippage. Don't treat the belts, just the pulleys. The oil to use: I use something from our local Fry's electronics store. 3 in 1 might work but it contains lots of petroleum that dissolves rubber, especially those teeny bulkhead ones securing the motor. It also is not likely to last very long.
 
monchito

monchito

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May 5, 2009
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gb check to make sure that the capstan rubber is good as its known to go bad that you will find around the capstan there is a wheel that touches that rubber sometimes its non existant and will cause it to eat tapes , or it may be there but real bad shape either dried up or about to become goo , most of the sharp series uses this in there decks gf-9494 ,9898, and i belive that one you have may have it also so check that :yes:
 
Ghettoboom767

Ghettoboom767

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May 6, 2009
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Thanks guys-I'll look into that when I open her up again-off to work tomorrow so when I'm done working -I'll get into it again.
I'm going to get some good machine oil and check that Head adjustment and look at all parts closely.
This is a nice boombox so it's worth it to get it going.
Have agreat week-GB. :-)
 
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