Servicing Technics linear turntables

[greenhorn]

I've read here that Technics linear's are too complicated, and people recommending against buying them. While they are more complicated indeed, probably as complicated as a turntable might be, they're not any more complicated than a full logic cassette deck.
I recently got an SL QL5 which I fixed up, and when I saw someone selling a non working SL 7 locally, I offered to fix it for free, because I wanted some more practice.


I watched this video to get an idea of how to do this, and figured it was easy

After opening the deck up, the entire mechanism in this too was fully gunked up with solidified grease. Used a lot of napkins, cotton buds and alcohol to remove it. Replaced the belt and put super lube, now things work just fine! The mechanism on both is very similar

Insides of the SL 7


With the Record size detector removed - the platter has holes through which light shines through, and there are photodetectors on the top of the board. You can of course block them to force a particular size using a switch on top. This is unlike the mechanical detectors on earlier automatics. The only problem with this is that you are stuck with the stock platter mat, and you can't upgrade. For this specific TT, the platter mat is literally stuck on

With all the junk removed and lubed with Superlube.

Multi-Purpose Synthetic Grease with Syncolon® - 21030

Tube

www.super-lube.com

This is what I use for the mechanism



This is just after a preliminary cleaning - there was 3-4 times more gunk to be removed


My Turntable along with the visitor


What the inside of my TT looks like - more or less the same, but strangely the belt size was slightly different


Now it works just fine

Disclaimer: this is only valid about the Technics mechanisms. Not sure about sony biotracer, denon , akai linears

 

[Saket]

Nice thread. First time I am seeing the internals of a linear tracker & it is simpler than what I had imagined. I think the controller IC, if gone would be hard to source.

Coming to opto-electronic disc size detector, some direct drive Technics turntables also use this optical arrangement for detecting disc sizes. I have one of them which is SL-Q33K. It has an InfraRed post standing tall on the deck which communicates with the receivers on the platter.

Thanks for your post.

 

[greenhorn]

my SL Q5, which is a linear uses mechanical sensors. there is one near the spindle, and one near the edge. the edge one is visible in the last photo
The next level models in technics hierarchy at the time had an optical sensor next to the tonearm which was used for detecting tracks, and was used for track skip and programed track play.
Another failure point, though somewhat fixable, is the wiring harness from the base to the top - which sometimes gets damaged with use and age.