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
rower 01-22-2016 1:19pm
I still have question about the other chips inside the MK3. Are they easily found, not as important or just don't ever die?

Someone like Bill T would have better first-hand knowledge, but in my research nearly all the examples I could find that had DN860 or AN660 failures had tell-tale signs of prior work that didn't appear very impressive.  I just didn't see any evidence of "spontaneous" failures for any of the other ICs like you do for the MN6042. 

The motor drive IC, AN640G, is still plentiful, but those don't seem to ever fail.  AN660s and DN860s still show on eBay once in a great while as have a couple MN6042 recently, but they're becoming few and far between unless you strip a lower model 'table. 

Not as easy as the MN6042, but I think something could be fairly easily made to replace the DN860.  That's not to say I think it'd be worthwhile though.  I've a bit over two months and well north of $1000 in to the MN6042 replacement. 

JP
If you ever get tired of your SP10MKIII endeavors, there are
a few anxious owners of Victor TT101,s hanging about.

The thread posted by Halcro previously "audio16" shows what
its all about.
Lewm has one that is currently not operable.
Interesting.  The SC3042 IC is similar to the MN6042.  Not sure it's worth while, but happy to have the conversation. 
Totem and JP, As you also may be able to glean from reading Halcro's and my recent posts, a few years ago I was able to find and buy about 10 samples of the SC3042.  In the last few weeks, I sent two of them to a fellow aficionado in Germany, known to us as "Thuchan".  Thuchan had evidently purchased a broken TT101 with Halcro's help, and his tech determined that it needed replacement of SC3042.  Until this recent episode, I had no idea whether the chips I bought (from a vendor in Hong Kong) were genuine or even in operating condition, but Thuchan's tech got his TT101 up and running perfectly by virture of installing the chip I sent.  This is great news for me as well, because I have more SC3042 chips on hand. (By the way, I think they are still available from China and Hong Kong.)

My own TT101 has been "broken" too, since purchase about 3-4 years ago.  For that reason, I got it at a low price, approximately the value of the tonearm that came with it.  I happen to live very close to Bill Thalmann's shop in terms of highway driving, and Bill early on replaced all the electrolytics in my unit.  However, in Bill's shop, once the lytics were replaced, the TT101 refused to misbehave.  It worked perfectly on each of two visits to the shop.  In my house, it worked only intermittently, and every time I began to feel confident about it, it would go "on the fritz".  I tried all sorts of black magic to no permanent avail.  Then I started to try to trouble-shoot it myself. Suffice to say that in the process of trying to fix it, I converted the intermittent problem to a permanent and consistent problem.  Also, I am pretty sure at least that the problem is local to the PCB that contains the SC3042, although I lack the expertise to prove it's the SC3042.  (There's more than one chip on that board, and the others are not SC3042s.) However, Thuchan's tech tells us that his unit was misbehaving in a way similar to mine, so now I have hope that replacing the SC3042 may finally fix it.  How's that for a saga?

Bill worked on my SP10 Mk3 and on my Denon DP80. He's a great guy, and we are lucky to have him. Now that my TT101 is reliably malfunctioning, I hope to take it back to him for the 3rd time to finally trouble-shoot it. Either that or I may send it to Thuchan's tech in Germany, if the postage is not prohibitive in cost.

JP, Are you in the DMV area?  I'm watching snow accumulate on my car outside.

I do think there would be interest in an SC3042 PCB re-creation, certainly on my part and especially if the discrete circuit can outperform the chip.
Nothing worse than an intermittent problem, so it was good you made it permanent. 

I'm in NYC.  Nothing here yet.