Apocalypse Now?—Technics sp10 problem s

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http://www.artisanfidelity.com/Detailed-restoration-photographs.html

Dear Banquo, Your verbal description does not paint a picture I can remember from having been "inside" my own SP10 Mk2. Perhaps I will take a look to refresh my memory. In any case, it is a relief to know that you don't have any spindle or platter wobble.

Now you say you have no plinth, it is possible that the vibration you experience at start-up is normal, if it goes away within a few seconds. The high torque of the motor WILL cause the chassis to want to spin in the opposite direction from platter rotation. (Remember Newton's 3rd Law of Motion?) At turn-on, max torque is elicited until the platter moves off from rest. During that brief period, it is quite normal for the un-anchored chassis to vibrate irregularly. I don't know whether this is the complete explanation for your dilemma, but it certainly sounds like this normal phenomenon is playing a role. In my own case, my Mk2 acted like it could walk off the shelf, when I started it up prior to its installation into a plinth. I daresay the Mk3 might actually take off in that scenario. Try physically restraining the chassis, and tell us what happens then.

Dear Lewm: if you look at the site rwwear linked to, and open up the second pic down on the left, you'll see what I was trying to describe. The spindle goes into the hole and the piece of metal above the hole is what is worn on my TT.

The vibration I notice today is definitely not a result of being plinthless. It doesn't go away seconds after start up, but rather remains as long as the dreaded buzzing noise remains. That is, for minutes after starting the motor for the first time. If I play records for hours after that the buzzing more or less goes away and so does the errant vibration. You are right though that being plinthless causes a very brief little shake right at each start up, but that's not what I'm referring to.

You've seen, I'm sure, the thread on the 'nude' Victor TT. I'm trying to see whether I like the Technics nude. So far no complaints. The Audio Technica feet are excellent, and serves to restrain and isolate the TT. Even with the errant vibration, the TT hasn't actually moved its location. And during play, I can drum on the platform the TT rests on without sonic penalty. I might try fabricating a plinth later but I see no reason to right now. The set up is ugly as sin, especially my makeshift armboard (which sits atop 4 Herbie's tenderfoots), but sounds delightful. Now if I had a MkIII, as you say, the motor on that is much more powerful and probably requires a plinth.

A couple of months ago my friend’s SP10 MKII had the same slight grinding noise at the bearing. At first, he thought it was the problem of either the main bearing or some of the chips under the turntable chassis. However, when we switched the separate power supply to the one I had, the problem went away. It turned out that some of the electrolytic caps in his power supply had gone bad. After he changed all the caps in the power supply, all is well, and even the strobe light, which hasn’t work for a long time already, is now working.

On the other hand, I have a SP10 MKII which has erratic speed due to a bad speed control chip. I was told this is not fixable since even Technics doesn’t have that chip in stock anymore.

There is so much "urban legend" surrounding these turntables, that it is difficult to find the truth.

Thekong, In fact, I doubt Technics has ANY parts for ANY of these turntables, but the chip you need may be the same as that used in later Technics tts, such as the recently discontinued SL1200 series and the related turntables (SL1500, SL1600, etc), some of which are available quite cheaply on eBay. Also, I found a supposed NLA chip for my Denon DP80 by doing an internet search which led me to a company in Hong Kong that is an information depot for many other small electronic supply companies in the Far East. Through their auspices I found enough of the Denon chips to go back into DP80 production, if necessary, for as little as 35 cents each. See if the faulty chip has an alphanumerical code on it, and put that right into Google. You may be surprised, pleasantly.

Banquo, I will take a look at the site. Now that you describe your problem in more detail, I still say that you should not be taking advice at a distance from us amateurs. Your problems might all be solved by changing out your electrolytic caps, which, as I said above, should be done anyway if not already done. But regardless, you need Bruce Berdan or Bill Thalmann or someone of that ilk. A good machinist can probably repair the worn part that you are looking at, assuming even that it needs to be done. One bit of advice I do have: don't be running the motor without the platter. Without the platter, the servo mechanism will be very unhappy. By the way, if you are using a very heavy platter mat OR a very light one, in relation to the weight of the stock rubber mat, try going back to stock and see what happens.

Re plinth-lessness: You guys are really doing two non-standard things; you are running without a plinth, and you have your tonearms mounted on a separate pod. I have an open mind about the plinth issue, but IMO it really is better to fix the tonearm mount on the same mechanical linkage with the turntable bearing. However, I know very well that some disagree.