Vintage DD turntables. Are we living dangerously?

 Under the platter, you will find a rocker switch labeled “run” or “hold”. In the run mode the tachometer will display the RPM from zero to the set value. For example if you are set to 33.33, then the tachometer will read from 0 to 33.33 over and over again. This can be very distracting.  Maybe that’s what you are looking at. Check that switch under the platter. Set it to hold and you will see a static display of the RPM. At least you should see that. If you see anything else, that is an indicator of a problem. Also, I would point out, with all due respect, that cleaning the contacts is not tantamount to changing all the electrolytic capacitors. Without meaning to sound dour, the more you power up the unit without having identified the problem, the greater is the possibility that one of the hard to find ICs is suffering a fatal calamity. 

Question for all you vintage DD experts out there.
I have just acquired a Technics sl10 linear tracker which looks to be fully functional and in good shape.

My question is concerning the RCA out.
It looks like it has a built in phono amp as the little button next to the RCA outs says mm/mc.
Does this mean it cannot be used through a phono amp as there does not appear to be a bypass to this , just choice of mm or mc.
Thank you

I definitely made things worst for my self.
and probably added more to a repair bill for moving those pots.
I hear that calibration cost $1000 for this QL-10? and I’m guessing that doesn’t include redoing the caps??
i wanted to fix it since it was my uncles.
worst come to worst, can I get a ql7 platter and still use my plinth and arm?
Thanks everyone for the responses.

It looks like it has a built in phono amp as the little button next to the RCA outs says mm/mc.
Does this mean it cannot be used through a phono amp as there does not appear to be a bypass to this , just choice of mm or mc.

I think it's only a gain-stage for the MC to boost the low output — there's no RIAA eq. So it can go into your phono preamp.

Pablo, I don't know where you "heard" that calibration of a QL-10 would necessarily cost $1000.  I believe that some time ago on this thread, JP Jones remarked that he could not hope to repair a malfunctioning unit for less than $1000.  That's a far cry from saying that it takes a kilobuck just to do calibration.  If the unit is functioning properly, a knowledgeable person, e.g., JP, could probably do the calibration for much less cost.  When the TT-101 is "broken", it is a real can of worms, which made JP's off the cuff estimate of $1000 seem fairly reasonable.  JP can comment if I am way off base, or not.