Vintage DD turntables. Are we living dangerously?

Halcro

I think it's the number of joints and the sheer complexity of their locations plus the triple layer stack of PCBs which must flex whenever they are handled for servicing that is the real problem.

You hit the proverbial nail on the head, the hole bugaboo regarding DD IC failures {in this case} should be finally put to rest.

I searched through my communications with my tech when he was servicing my tt 101. Below are some pertinent quotes on the construction of the boards and how he went about fixing the table:

--There were no bad parts, just bad connections. I ended up resoldering all the feed thru eyelets, then flipping the board and removing the solder with a sucker, then resoldering them with much less solder. They all look pretty clean now. I know other companies that used the eyelet method had reliability problems. For some reason the solder cracks around the eyelets, probably related to different coefficients of thermal expansion.

--Besides I took a lot of solder out of those eyelets. The issue is the eyelets are hollow so they don’t fill with solder. The hot air insides always bubbles the solder out. I put just a bit around the edges and then cleaned the flux with acetone.

--The PCB is two sided but without plated through holes. It looks like they put eyelets in and then solder on both sides. I found one that was open but by the time I pulled the PCB it was connecting. I resoldered it and now the 45 light comes on and that speed works. The 33 light never comes on so I think there is something wrong with that flip flop. It is made of all discrete transistors so it is really hard to figure out the logic flow.

--I’m always amazed when someone would design a product as complex as this, with a high price, and not spring for a plated thru board. It boggles the mind that they would have relied upon these eyelets which are labor intensive.

Hope it helps someone.

Hi Totem,
I think, as you say.....the most encouraging part of this exercise was the fact that every transistor of the 40 that my Tech took out and tested was perfect.
The ICs were more difficult as many of the test figures in the Victor Service Manual didn't make sense or were simply wrong.
In any case....all the original ICs were also fine.
So it bodes well for most vintage DD decks out there (which certainly have nowhere near the number nor complexity of solder joints of the TT-101) that they are a good chance of continuing their 'normal' service for the foreseeable future.
And with the seeming cutback in production of Harry's VPI Direct at $30,000....that's good news 😃

Thanks Banquo,
That quote from your Tech is invaluable....

Halcro, You wrote, "The ICs were more difficult as many of the test figures in the Victor Service Manual didn't make sense or were simply wrong." Are you referring to the DC voltages on the pins of the ICs? I ask, because I measured some of the voltages at the pins of one IC that is suspect, and they do not at all match the predicted readings posted in the Service Manual for that IC. This led me/leads me to believe the IC may be faulty. But if my interpretation of what you wrote is correct, maybe I need not worry about it, unless or until I have further evidence of its malfunction.
Please confirm.

Banquo, where do you live, and who is your tech? Is it Bill Thalmann? Thanks.