Vintage DD turntables. Are we living dangerously?

Kind of gutsy for HW to point out the problems inherent in belt drive, elsewhere in this blurb, since he has made a living from belt drive heretofore.

Yes.....seems kind of strange...?
Almost like Linn coming out and saying they've finally seen the light......and it ain't belt-drive?!

What is equally amusing to me is the fact that the motor Harry uses in his DD....is the same as that used by Continuum in their Caliburn and Criterium turntables designed over 10 years earlier whilst his 3D printed arm follows the Continuum Cobra and Copperhead initiative again produce 10 years earlier?
Methinks Harry has had meaningful conversations with Mark Doehmann...the original design chief at Continuum?

Sorry to hear of your continuing hassles with the TT-101.....
One suggestion I have (as this intermittent fault will never seem to replicate itself in front of witnesses.....is for you to take the TT-101 downstairs to you listening room and remove the metal protective shroud, plug it in and play it.
If it works like it does in the kitchen.......continue on till it misbehaves at which point touch and move all the connecting wiring and see if that affects it?
I'm not convinced by your 'movement' theory.....but as the turntable CAN perform properly at various locations for long periods of time......there should be no reason why it can't be made to do so down in your listening room?

Alternatively....when the problem presents itself.....follow the 'Troubleshooting' procedures outlined on p.25 of the Service Manual. They are very detailed and clear.
From a brief scan of this page related to your problems.....I would bet on one cracked or broken wire or a malfunctioning transistor/s....
Both relatively easy fixes?

Halcro, Luckily for me, I have two systems, one of which is on the same floor as our kitchen, if it should come to that. So push come to shove, I can as well use the TT101 in my "upstairs" listening room. But I really do not think there is anything going on related to the basement environment. I don't know why you are not convinced by my observation that malfunction occurs after the TT101 is physically picked up and moved from one room to another, or shipped, or transported in my car. It's just a fact, one of the only consistent findings. Also, once it is up and running properly, it very consistently runs properly from then on. Which is why the last repair guy never could duplicate the problem. He told me that what he did was to turn it on and leave it on, for a week in his shop. Since the problem only occurs at start-up, and not thereafter if start-up has gone well, it is no wonder he could not reproduce it. One could say he never really tried to reproduce it, since that requires starting and stopping the tt. But he treated me like I was a moron who needed hand-holding, so I am happy to have it back in my possession. (I am not referring to Bill Thalmann, who is a great guy and very attentive.)

No malfunctioning transistors. First, Bill checked them all. Second, a transistor does not give an intermittent failure; it's either good or bad. However, the wiring up to and out from a transistor could certainly be "cracked" or more likely cold-soldered.

Nilsvala, Any SP10 should be reparable, because the only unobtainable part in an SP10 is one single integrated circuit ("chip") that is no longer made. However, the same chip was used in the SL1500, 1600, 1700 series, and some of those are so cheap that it is not a problem to buy a whole tt and cannabalize it for that part, in order to keep an SP10 in service. If you need specifics, I can try to find out exactly what models to buy. Albert Porter has done this several times for himself and his friends. I believe he stockpiled a few extra chips salvaged in that manner.

I believe Lewm is right that there must be a cold solder joint somewhere or a pot that needs lubrication where the wiper has intermittent contact or a crimp connector eroded over the years and lost contact. These kind of things require only the merest movement to knock it out of wack. The ghost is in the detail.

Happy witchhunt!

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However, the same chip was used in the SL1500, 1600, 1700 series, and some of those are so cheap that it is not a problem to buy a whole tt and cannabalize it for that part, in order to keep an SP10 in service. If you need specifics, I can try to find out exactly what models to buy.

Lewm, I would be very grateful if you could find out which specific models to buy, thank!

Thuchan sends his greetings......
The funny thing was that the Sony PS-X9 was located only 10 miles from where he lives.......so he drove it home very slowly.
He hasn't had time to listen to it as he leaves today for sunny climes.....