I have a pair of 112 cassette decks and both of them have issues with the pitch speed control.

When i bought them, both decks needed belts and the pitch speed control was jacked. When i enabled the pitch control button the motors go into full fast speed with the heads still engaged of course.

Deck #1: I bought the replacement variable pot for the speed control board, and that worked to restore proper operation. Now a few years later i can hear that the normal mode play speed has increased slightly.
Maybe just a tweak to the speed trimmer on the cassette circuit board???

Deck #2: normal play speed is fine, but pitch control enabled speed goes off the rails as deck #1 did. I will try pot replacement there as well IF i can still get it from Tascam parts, but...

The question is....

Has anyone else had these issues with the pitch control? And there any other things I should be looking at?