Vintage DD turntables. Are we living dangerously?

I have just acquired a 32 year old JVC/Victor TT-101 DD turntable after having its lesser brother, the TT-81 for the last year.
This is one of the great DD designs made at a time when the giant Japanese electronics companies like Technics, Denon, JVC/Victor and Pioneer could pour millions of dollars into 'flagship' models to 'enhance' their lower range models which often sold in the millions.
Because of their complexity however.......if they are 'unobtanium'....and they often cannot be repaired.

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. 

@lewm Tuchan’s technician in Regensburg, Germany:
He stated the estimate cost at 1000 Euro for repair.
thanks @halcro 

Hi guys

@lewn I read many times this and other threads to understand the problems of TT-101 and I reported all the information possible to the repairman but the conclusion was a failure.

Unfortunately, the TT-101 is a complicated and delicate turntable, each operation requires to mount everything and try, disassemble and reassemble disassemble and reassemble continuously with the risk of breaking a cable or other; all this is frustrating as well as increasing the hours for waste of time.

I also read the comment of chackster for the cost of 1000 € is madness ........ you can look for another TT101 running for that price and keep the other TT-101 dead for spare parts.

Unfortunately the hourly costs of a repariman are high all over the world ..... it would be necessary to find a retired repairman who does it for passion at a flat rate.