I offered to post a solution months ago (post #2) but never did. Apologies to all — and Hitachi, thanks for your patience. Ksteufert's recent post prompted me to get off my ass.
I have the D8 tonearm right in front of me. It's a very good arm. I've used it with both MM and MC with great results, so it matches a wide range of compliances. In fact, I got a second YP-D8 TT that was badly damaged in other ways, just so I could recycle the arm to use on another table. It's that good. It was designed by Micro Seiki, has extremely low bearing friction, and even provides VTA adjustment on-the-fly — at least it
should. They sing its praises on the Vintage Knob...
http://www.thevintageknob.org/yamaha-YP-D10.html
Mine had the same problem you all describe — it took so much force just
trying to turn that adjustment-ring at the bottom of the post, that the stylus skipped all over the record. Even when not playing a record, it was impossible to adjust VTA. Useless. So many of you have the same issue, it must be common. Here’s how I fixed mine...
The entire arm assembly slides up and down that thick, chromed post (at least it should). I took the tonearm off the turntable. Then I took the whole arm assembly off the post to see what’s inside. There’s a smooth white plastic sleeve wrapped around the post (with a slit down the side for removal). It was lubricated with brown grease which was old and clotted — more like glue than lubricant. The same grease fouled the adjustment ring and the fine thread on the post which it engages.
Problem solved! It
seemed an obvious reason why it wouldn’t move up and down anymore. So I cleaned all that dried-up grease off, relubed it, and reassembled. Like new, should be perfect now. But guess what? No change! Still frozen in place.
I was baffled. As an experiment, I removed the plastic sleeve completely. Now it worked perfectly — the adjustment ring turned easily, the arm glided up and down smoothly. I could change VTA while the record played (no skipping) so I could hear the effect in real-time and “tune” VTA perfectly. And just as importantly, the arm locks in place with total rigidity once VTA is set.
To verify my results, I put the sleeve back in — and the mechanism was totally jammed again. I repeated this two or three times, trying every possible variable (there aren’t many). With the sleeve in, it jammed every time — without the sleeve, it worked perfectly every time.
So I just left the plastic sleeve out. I went through some head-trips about it — how could I be smarter than Yamaha? — it must have worked when new, and I saw nothing to show why it no longer worked. The dead old grease was a logical explanation — but wasn’t after all. And that sleeve was in perfect condition when I put it back in — smooth and shiny, no damage, no deformation, not even a scratch freshly lubed with high-grade aerospace stuff — and still didn’t work.
Every time the sleeve was in, it jammed. And every time it was out, it worked. That sleeve been out to this day, a dozen years later, and the VTA-adjustment is smooth and easy.
That’s the “fix”. It sounds odd, I know, but it works. I wish I could explain why, a solution is never totally satisfying if you don't know why. The only thing I can think of is maybe that plastic sleeve swells up over time — any thickening would jam the gap it needs for free movement.
I hope it works for you. If it doesn’t, it will only cost an hour of your time. You won’t damage or alter anything and can easily restore it to its original condition. If you try it, please let us know your results. And if you figure out the "why" please enlighten me.
