Speed stability issues with my Teres turntable...

After 18 YEARS of flawless service, my Teres 155 series turntable has developed speed instability issues. Sometimes the red light comes on. But even when it doesn't, I can hear it. It's gotten to the point I don't want to listen to it anymore. I've already done the usual drills such as rebooting the motor (non battery version), replacing the belt, etc. The motor has STILLl got torque galore, so I don't think it's failing yet.
Could it be motor speed controller circuitry components failing? Hope not-I've got the schematic for that, but don't have the technical know how to trouble shoot that. I've already done a search, and will be looking into the bearing well, checking the bearing, and checking the tightness of the pulley. Any other suggestions would be greatly appreciated! :)
Check the side to side bearing play on the motor.  If you got 18 years out of that motor you did well.  Those Maxon motors do not like a lot of side load.  If you can do your own work check out the DIY forum and the the motor controller threads over there.  Bill/ Pyramid has a great thread with almost step by step instructions.

Enjoy the ride

I'm not sure which motor Chris used on the early Teres tables but if it's the same motor Thom Mackris used in his Galiber table that motor is no longer available. I emailed Maxon a couple years ago and this is their reply..

My name is Eugene and I am a Motion Control Applications Engineer at maxon. I received your inquiry for a replacement motor for your current S26, Precious Metal Brushes, 4 W (2326.933-12.111-050).


The motor that is the closest replacement for your S26 motor is the A-max 26, Precious Metal Brushes CLL, 4 W (110169). Please see below for the cross reference.


S26                                         A-max 26


Speed Torque Gradient (rpm/mNm):                     181                                         190

Speed Constant (rpm/V):                                             1330                                       1380

Torque Constant (mNm/A):                                       7.19                                       6.94

Have you cleaned the pulley / platter with rubbing alcohol?

Good Luck!

Have you checked with Chris?

I really miss an active and vibrant Teres community. I'm always interested in ways to optimize my table (essentially a cocobolo 245 w/ a Verus motor). I'd love to get my hands on a lead-loaded platter.
Those were the days when some real smart guys did some brainstorming and came up with rock solid ideas for the diy community.  Not a bunch of marketing b.s. or ego based crap.

The lead loaded platters are the real deal.  Mine are aluminum,  but heavy outer rim lead really helps almost any material.

Enjoy the ride