Yamaha YP-B2 drive pulley height

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Ionovac
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Yamaha YP-B2 drive pulley height

Post by Ionovac » 12 Aug 2019 01:10

I’m trying to get my girlfriend’s long neglected Yamaha YP-B2 running again. I found a belt, and a dealer friend set up a Grado Black in the head shell. The one remaining issue is the alignment of the drive pulley with the speed changing yoke.

Right now, the 33/45 switch drags the belt to two positions, neither of which corresponds to a step on the pulley. There’s an eccentric adjustment for the yoke, but it only moves it a tiny bit. It looks like the drive motor is sitting too low.

The service manual says to set the drive motor height before adjusting the yoke, but doesn’t say how, and the exploded diagram isn’t too helpful. Is anyone familiar with this table or the setup?

Alec124c41
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Re: Yamaha YP-B2 drive pulley height

Post by Alec124c41 » 12 Aug 2019 05:37

If you look at the drive spindle, below the belt area is a small set screw. Loosen it, set the spindle height, and tighten the screw.

Cheers,
Alec

Ionovac
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Re: Yamaha YP-B2 drive pulley height

Post by Ionovac » 12 Aug 2019 14:44

Great, thanks!

Ionovac
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Re: Yamaha YP-B2 drive pulley height

Post by Ionovac » 18 Aug 2019 16:44

Further issues: The motor appears to be sitting very low- possibly lower than can be compensated for by adjusting the position of the pulley. This TT has been sitting in a cabinet for 15 years, before which it was in regular use (long story). Does the motor sit on some sort of compliant rubber suspension that might have decomposed, like the belt? I suspect I’ll end up having to put this on my bench at home (it’s at my girlfriend's) to get it all sorted out.

Ionovac
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Re: Yamaha YP-B2 drive pulley height

Post by Ionovac » 18 Aug 2019 18:06

Problem solved: I removed the speed change mechanism. 😄 Girlfriend has no 45s and no plans to buy any, so no loss. I saved the parts, of course. I’m pretty impressed with the sound.

nat
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Re: Yamaha YP-B2 drive pulley height

Post by nat » 19 Aug 2019 23:23

Nothing useful to be added, but I admire your VE name, Ionovac. Great tweeter, apparently, though there is controversy about whether they produced ozone in appreciable amounts, ozone being a known health hazard. I saw a pair once, at the Aberdeen Proving Grounds in Delaware, which was where the DOD had surplus auctions for scientific equipment. Alas, they were sold already, though Lord knows what I would have done with them if I had got them.

Ionovac
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Re: Yamaha YP-B2 drive pulley height

Post by Ionovac » 22 Aug 2019 00:28

I saw a non-functioning pair in a research lab I worked in long ago. Couldn’t find a way to test them, or to walk off with them ;-)

Alec124c41
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Re: Yamaha YP-B2 drive pulley height

Post by Alec124c41 » 22 Aug 2019 01:39

Nelson Pass apparently tried to make a pair of full-range ion speakers.
https://www.youtube.com/watch?v=msE14cWTwKI&t=16s

Cheers,
Alec

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