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.
TT-101
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 malfunction.....parts are 'unobtanium'....and they often cannot be repaired.
128x128halcro
Aigenga,

You tightened the bottom bearing well too tight, this one is used to set the height of the rotor inside the motor housing.  You should re-examine this assembly.  The reason that the bottom plug was secured with a "clay like material" was to prevent it form coming loose.  tighten it just so much that you get a rub with the top cover on the motor on, then back it off a quarter turn, then secure it with a dap of nail polish or similar.

Best of luck

Peter    
Regarding the transistors used in the TT-101 I want to make sure that I can get the table working with the new ones installed, I'm still a little ways away form this.

Once I get it going I'll let you know the appropriate replacements

Good Listening


Peter





ps68, You've independently hit upon exactly the reason I went off on a craze over these vintage dd turntables.  In the end, the better ones are the best bang for the buck.  Plus, the drive and rhythm that they can impart to music are addictive and unique.  The best idler-drive turntables are of a similar flavor.

To all: The problem with my TT101 seems at the moment only to have been a tiny crack in the main PCB, right near the edge. JP thinks it occurred during manufacture, 30-odd years ago.  The circuit was only maintained by solder, and once the solder cracked (invisibly, I might add), the result was a fault in TT101 function that was manifested intermittently, depending upon stress on that PCB.  There was no need to replace the SC3042 chip in mine or indeed any of the discrete transistors.  Great work by JP to find this problem, only made possible by the fact that the thing finally malfunctioned in the presence of a smart guy who knew how to trace down the cause.  Other such problems are being searched for, just as a precaution before I get it back. I hope this is not premature, but I am very pleased.
Lewm,

Absolutely, the top end of the late 70's DD era will never be repeated, and many of them are still very viable contenders when it comes to proper high fidelity. The limiter is finding them in unabused condition, and knowing a good service tech if anything needs doing. Beyond this, with careful design one can build a vinyl front end comparable to any very costly current piece. I have a DP80 also, which I will base my next TT on, after the TTS 8000 is fully finished. This so rewarding when it works well.. 

Glad you may have got the Victor sorted, good work finding the fault by your guy.. 
PBN, Was reading your instructions to Aigenga with interest, since I think I may have a go at cleaning and lubricated the bearing in my unit, once I get it back.  Seems to me that loosening the plug, which I assume means turning it counter-clockwise, would have the effect of lowering the bearing/spindle/platter such that the outer edge of the platter might ultimately rub against the escutcheon that surrounds the upper level circuitry and the tachometer and switches.  "Tightening" the plug, which would make it move upward into the chassis, would seem to me to be the way to relieve that condition.  This, I think, is the opposite of what you wrote.  However, since you may have worked this out with your TT101 right in front of you, I am thinking that maybe I do not understand the anatomy of the TT101.  Please by all means correct me if I am wrong in my concept of the relationships among these structural elements.
Thanks.