CT-F9191 play belt

[tnbriggs]

Took my CT-F9191 to my local repair shop. Wasn't working either in FF/RW or play/record. Techs replaced the belts and demagnetized the heads, etc. But the play/record belt keeps walking off the drive motor shaft. They replaced what they'd put on with a slightly longer belt (which seems counterintuitive to me), but the same thing happens with it. I've removed the case and can get the belt back on and run it, but after a 90 minute tape or less, it walks off again. FF/REW seems to work fine.

I've ordered the WJOE belt kit and when I get it I'll try to install myself.

I've been through a lot of the CT-F9191 threads and can't find an identical situation. My thoughts are that the replacement belts installed by the local shop are just not the right belt. Seem right?

 

[zebulon1]

The brass pulley attached to the capstan motor can be adjusted for proper alignment to the capstan pulley.
There’s a small Allen set screw that might of loosened on the motor pulley.
WJOE includes the proper wrench when purchasing the FF/REW motor tire. I can’t remember the wrench size. It’s small.
The capstan pulley it self has to remain stable and uses a low friction setup. You might want to check and make sure all the required parts are installed. The capstan pulley should have almost no fore and aft movement.

 

[tnbriggs]

The brass pulley attached to the capstan motor can be adjusted for proper alignment to the capstan pulley.
There’s a small Allen set screw that might of loosened on the motor pulley.
WJOE includes the proper wrench when purchasing the FF/REW motor tire. I can’t remember the wrench size. It’s small.
The capstan pulley it self has to remain stable and uses a low friction setup. You might want to check and make sure all the required parts are installed. The capstan pulley should have almost no fore and aft movement.

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Thanks for the input.
I checked it (mine's a slotted set screw); it's tight and I couldn't tighten it any more on the motor shaft, but there is a slight bit of in/out movement (1/8"?) of the pulley & motor shaft. The belt just walks off the open end of the pulley; rides up on the outboard pulley flange, tape speed and pitch increase, then rides off the end and then the unit stops. I'm getting pretty good at resetting it by now.

 

[tnbriggs]

+++++++++++++++++
Thanks for the input.
I checked it (mine's a slotted set screw); it's tight and I couldn't tighten it any more on the motor shaft, but there is a slight bit of in/out movement (1/8"?) of the pulley & motor shaft. The belt just walks off the open end of the pulley; rides up on the outboard pulley flange, tape speed and pitch increase, then rides off the end and then the unit stops. I'm getting pretty good at resetting it by now.

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Correction to last post:
In/out freeplay more like 1/16" than 1/8".

 

[zebulon1]

I guess, wait and see if the new belt from WJOE works before getting to deep.
I believe the motor pully manages the belt alignment and the capstan is the follower. The capstan should float between the belt cavity with little friction.
Have you pulled the capstan pulley and stem out for an inspection?
Double check with the exploded parts diagram for the bits on that assembly.

 

[tnbriggs]

I guess, wait and see if the new belt from WJOE works before getting to deep.
I believe the motor pully manages the belt alignment and the capstan is the follower. The capstan should float between the belt cavity with little friction.
Have you pulled the capstan pulley and stem out for an inspection?
Double check with the exploded parts diagram for the bits on that assembly.

+++++++++++++++++++++
Thanks again for the response. I will likely fiddle with it until the WJOE kit arrives. I took a short video of the condition; file is here: https://audiokarma.org/forums/index.php?media/ctf9191-beltslide1.24266/
There is a tape in the deck but it is not being played. The unit is powered off. When I turn the unit on, the play/capstan motor spins (as it should when a tape is in the unit, from the service manual description) and when the belt is in the correct position on the pulley there is a slight rotation noise for about 1 second. Then the belt slides to the flange at the end of the pulley shaft, still turning, and the rotational noise stops even though the belt is still moving. Tape play was never started. I then turn the unit off.

 

[tnbriggs]

I guess, wait and see if the new belt from WJOE works before getting to deep.
I believe the motor pully manages the belt alignment and the capstan is the follower. The capstan should float between the belt cavity with little friction.
Have you pulled the capstan pulley and stem out for an inspection?
Double check with the exploded parts diagram for the bits on that assembly.

+++++++++++++++++
After a week of fiddling with it, I took it back to my local shop again. We un-cased it and he saw the belt roll-off first hand. Solution to remedy was to detach the capstan/play motor and flip it 180 degrees and then re-mount it. Apparently the rubber isolators in the motor assembly had worn and the wear was allowing the roll-off. Seems to work for now but I may be in the market for a new capstan/play motor sometime. I've sent a note to Pacific Stereo to see if they still sell their universal capstan motor. Thanks for your help.