Vintage DD turntables. Are we living dangerously?

I think the point of this thread, most of all, is that we don't have to give up on our vintage DD turntables purely for reasons of their having aged into obsolescence and unrepairability.  In general, they can be brought up to date functionally, and they can be repaired if malfunctioning.  In other words, we are not living dangerously.  Prudently, maybe, but not dangerously.

@chakster News for your TT101?

My TT 101 did not solve the problem of power loss with the slowing of the revolutions.

I heard the repairman a few days ago and he seems to want to give up; too much time lost to solve the problems that have been solved at 99% (I entrusted him to him in July 2017) too many hours spent and an expense account that could rise dramatically even more if you had to keep looking where the defect is .

So many welds are reworked and redone, but the problem remains, no capacitor replaced, his thought does not accuse the capacitors for this problem; 100 may be the reasons for this last flaw and from what I understood the problem could also be in the engine.

Without a working TT101 to have on the side to make the measurements it becomes impossible for him to go on; even the service manual does not help him, he says it’s bad,  there are no all indications for the measuring and calibration points, there are no indications to solve the problems such as the drop in laps; the service manual of the simplest Technics SP 10II is much better.

I’m desperate to hope to bring it back to life before starting my restoration :(

@best-groove 

I was lucky because my second TT-101 which i bought as a donor was better than first one! Actually it is working, but to start the platter i have to touch it by my hand, and then everything works just fine. Funny, i bought this turntable as a junk. 

My first TT-101 that i bought as working unit (not junk) and paid more for it, does not work correctly (as it was described earlier), i mean it works fine, but only for 30 minutes (more or less) and then turned to "stand by" mode when the platter stops energising.

-The JVC Victor service in UK is one of the options, and communication is good. 

-German service is another option, but the communication is not that good. 

-JPjones is propably the best option, but he's in NYC 

-There is another person who can fix it, but too far away in Australia. 



  

Those of you who live in Europe might consult "Thuchan", who posts here from time to time.  He evidently found a genius somewhere near where he lives (Bavaria?) who has a comprehensive understanding of this circuit and was able to repair Thuchan's TT101.  Thuchan's real name is Eckard; I have no idea where he got the moniker he uses.  He is a very nice guy.  I sold him a chip to help in the repair of his TT101.

If your TT101 needs a push start or a touch of the platter, it most likely is NOT running optimally, even if the tachometer reads out correctly.  Sounds to me like it might at least need to be calibrated, because the symptom suggests that torque is suffering.  This is JP's lament; most of us do not know the true potential of these DD turntables, because most un-serviced tables are out of calibration after 40 or more years.  
 
Best-groove, I got in trouble with Raul and Downunder for harping on the need to replace electrolytic capacitors, but in your case I would ask the repair guy why or how he has ruled out a leaky capacitor as the cause of or a factor in the repair of your unit.  After all those hours of effort, it would take only one or two more hours to just do it. Other known issues: (1) micro-fracture cracks in the PCB that can cause short circuits if they cross traces in the PCB.  (That was the problem in my unit, which you say had problems similar to yours.) You almost need a magnifying glass to see these defects. Your tech needs to know where to look for these, based on the nature of your problem.  (2) the PCB itself absorbs moisture in a humid environment which can cause malfunction.  I got these tips from JP, after he worked on mine.

Sadly, Lew, a fair number of serviced units aren't in calibration either. 

Freeze spray helps, as does not being afraid to twist the board back and forth a good 30 degrees or so.  This will likely cause more joint issues, but they were about to become issues anyway. 

This is why, when I was working on such things, I charged so much for the TT-101.  It takes a lot of time when your goal is to try to ensure that particular unit never sees your bench again. 

BTW, I think the TT-101 service manual is excellent - far better than the SP-10MKII.  Granted, there are no troubleshooting flow charts, but they do go through great pains to explain how the circuit works.  The downside is you have to take the time to actually understand it.

@chakster, you likely have a fractured joint or trace on your board that is opening after the unit warms up.  The self-shutdown is due to an over-current condition in one or more of the drive amps.  This protection is there to prevent things from burning up should the motor be stalled.