Asking help for tt motor speed unstable

Asking help for tt motor speed unstable

It happened just a few days ago when the driven string my Micro SX8000 was broken after the replacement of a new string. Then, I found the speed unsteadily fluctuated.

I has checked the string tension, the platter floating air pressure, the power supply voltage, even though the pcb of the motor having splayed some king contact point cleaner, but the speed is still unsteady.

Is there anyone met this problem before and offer any help?
motor speed unstable

my problem is solved by using some pine resin melted in alcohol liquid.

when it become sticky use a stick of cotton bar dip some liquid, and rub the string when the platter is turning.

afterwards, when the string is dried, the string is sticky then.

that is the increasing friction of the string stabled the fluctuating speed of the platter.

it is cheap but works.