Where can I purchase a replacement pinch roller and locking nut?

if you want to set your playback speed exactly right, you need a test tape with a test tone on it (3khz for example). now you hook a frequency counter to your tapedecks output and set the speed accordingly.

I had a similar problem that happened to my old Betamax camcorder. The only way that the pinch roller can be replaced is the whole cassette mechanism had to be replaced which was way too expensive and not worth the fix. And that was coming from a Sony certified repair shop.

This should help. Good luck !

Cassette (Tray 2) paper pickup and feed rollers

To remove the paper pickup and feed rollers

1 Remove the cassette.

2 Locate the two rollers on the bottom of the paper pickup unit (above the cassette). The pickup

roller is the smaller roller, and the feed roller is the larger roller.

3 Pinch the tab on the end of the cassette pickup roller (callout 1), and pull the roller out.

4 Pinch the tab on the end of the cassette feed roller (callout 2), and pull the roller out.

Figure 6-24 Removing the cassette pickup and feed rollers

Note Always replace the cassette pickup roller and the cassette feed rollers at the same time. Also replace
the separation roller (located in the paper cassette) when replacing these rollers

I am no expert in Akai units but the GX-635D I was working on had a screw off cap and then there was a nut that unscrewed to get the Pinch Roller off. That is all I can say as far as help- the cap should unscrew counter clock wise.

You put the two flat sides on the end of the cap nut and lock them in a vice. You then put a wrench on the back side of the chuck which also has two flat sides. with the cap nut locked in a vise take the wrench and turn the retaining sleeve which has the two flat sides counterclockwise to break the cap nut loose. When it turns freely take the chuck out of the vise and turn the cap nut off. You then push the ribbed locking sleeve down to access an o-ring. You pull that off and it releases the locking sleeve and two roller bearings. You then pull off the retaining slv with the two flat sides and release the other two roller bearings. the chuck will then just pull off the shaft

Hope this helps

I think pinch roller lock is broken,its not moving cassette.Please check it pinch roller is inside or not

Another roller type thing, attached to baseplate, squeezes the tape against that roller to drive/guide it.

It is really easy to replace the roller. You open up the scanner using the pinch tab on the front and lift the lever that holds the rollers and pull them out to replace them with new ones. New rollers can be purchased on ebay.

You are missing pinch roller lock, its like piece of plastic tube 2 or 3mm (1/8 inch)
This part is not available individually as you need to purchase complete "pinch roller assy" and fixing it requires skills and experience of camera repair.