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Technics SP-10 mkII speed adjustment question

Hi,

I'm on my way to complete my Technics SP-10 mkII project. Actually, a friend of mine, a professionnal audio technician, is working to upgrade the PSU, which is done but a small adjustment on the speed must be done and he need some cue on this issue.

We already asked Bill Thalmann, Artisan Fidelity and Oswald Mill audio. Plus, I'll post on DIY Audio today. We'd like to get the answer as quickly as possible to finalized this for the week-end. Hope someone on Audiogon can help.

Here's the message from my technician:

"Hello,

I'm an electronic technician and I do repair for audio equipments, vintage, hifi pro and more. I have a client here that brought me his turntable Technics Sp-10 MKII to fixed. I have a little question about it and he gave me your email because he pretended that you have some experience with this kind of materiel. So, hope that you can response my technical question.

I replaced all capacitors in the power supply and a big solder job. I checked for defect solders or capacitors on the circuit boards inside the turntable and I tied to do the adjustments . Everything seem good right now, the turntable work fine. I tried do do the period adjustment with the VR101 and VR102 potentiometers like in the service manual ( see attachment, Period adjustment method). When I looked the stroboscope at the front of the turntable, It's pretty stable but I can see a tiny rumble at 33 1/2 and 78 speed. 45 is the more stable speed for the stroboscope. So, I fixed the phase reference with T1 at 18us of period and I try to do the period adjustment at the point test T and S on the board with the O point for reference. When I put my scope probe on the T point, I can observe the stroboscope running. It is not stable at all. If I pull off my probe, the stroboscope is stable again. So When I have the 2 probes at point S an T at the same time to do the adjustment, it's impossible to fixed the wave T because it going right to the left on my scope. When I turned the VR101, the T wave going faster or slower but never stable. I tried to ground lift my scope, plug it into the same power bar and try to pull off the reference at the O point. I can't have a setup that I can see a stable T wave in my scope with the one that I can do the right adjustment. Why? Is there a problem with the turntable or maybe it's a incorrect probe or ground setup? Please let me know what you think.

Best regards"

Thanks for help,

Sébastien
128x128sebastienl
weisselk
48 posts
 
For a government research scientist, Richard, you don't seem to understand much.

My company employs technicians- in other words we pay them. They do not work for free. We do not provide free assistance to other technicians who cannot figure out a problem.

Guess you did not understand the part about OMA creating a completely new motor control for the SP10, either. But then again, we're not "techies."

Too funny.

Jonathan Weiss
OMA
lewm
13,296 posts
 
Who is Richard? In any case, the point is that you do have technical capability (or rather, your company does) but that you will not supply it to the OP free of charge. Since you are in the audio business, this is perfectly understandable. I'm still not sure why it's "too funny". Kudos to you on your de novo motor controller. Do you also repair defective SP10s? If so, I gather you would work on the OP's unit, if he were to send it to you. Excellent. Obviously you are a techie, and I was in error.
sebastienl's avatar
sebastienl OP
84 posts
 
Hi Lewm,

You were right. I think that Audiogon is not the more technicaly oriented site. Let me tell you that DIY Audio surprised me because I don't have any answer there.

Then, about some email I send to companies, M. Weiss explain the answer he gave me by his personnal email to me.

With the search I've done I was looking for:

1) get an answer from the community;

2) get an answer from a company with a sense of community in it.

The winner is M. Bill Thalmann. He answered to my audio technician with professionnalism and a great sense of share.
In the end, like an old university teacher once said
"We don't teach what we know. We teach who we are."

I know that there is still a great sense of community left in our hobby and passion.

Have a good day,

Sébastien
chris74
99 posts
 
We also do not provide free technical service but referred the OP to a certified technician we recommend in Chicago for advice. Our certified technicians are not available for free technical advice or assistance. In the event the OP should decide to send in his Mk2 for service, we would obviously be able to repair/service his unit accordingly.

Christopher
Artisan Fidelity
lewm
13,296 posts
 
Sebastien, I am very glad to hear that you got help from Bill. I feel very fortunate that I can get to his shop from my house in only about 30 minutes, and once I get there, I know absolutely that my equipment is in the best possible place for repair. I was rather surprised, actually, when you inferred in your first post that Bill was unable or unwilling to help you; on both counts, I would have expected him to come through for you. Glad to know that this is indeed the case.

Christopher, as I also remarked to Jonathan, I think your position is entirely understandable. I meant no slur on either of you, when I wrote that your respective companies were not "techies". What I really meant by that is that you are not primarily in the business of repair or of offering highly specific technical advice over the phone. If I was wrong even on that level, thanks for the correction.
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