Thorens tp90 tonearm

music box
babadockia
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Re: Thorens tp90 tonearm

Post by babadockia » 13 Nov 2019 21:51

StephDale wrote:
13 Nov 2019 21:41
The bit that turns with the tonearm. Have a play while watching the circuitboard assembly under the tonearm and you'll see the sector-plate piece (shutter) moves with the tonearm. It looks to need turning about 50-60 degrees.

Steph

That black thingy?

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Re: Thorens tp90 tonearm

Post by StephDale » 13 Nov 2019 21:56

Yer! :D

More seriously; put the arm in it's rest and check the position against the photo I posted. It must cut the light from reaching the optical detector, otherwise the turntable won't run.

Steph

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Re: Thorens tp90 tonearm

Post by babadockia » 13 Nov 2019 23:49

StephDale wrote:
13 Nov 2019 21:56
Yer! :D

More seriously; put the arm in it's rest and check the position against the photo I posted. It must cut the light from reaching the optical detector, otherwise the turntable won't run.

Steph
I'll do it some day really soon. Thank you. Actually the turntable runs, it spins the platter is just that the tonearm is not engaging

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Re: Thorens tp90 tonearm

Post by babadockia » 14 Nov 2019 14:50

StephDale wrote:
13 Nov 2019 21:56
Yer! :D

More seriously; put the arm in it's rest and check the position against the photo I posted. It must cut the light from reaching the optical detector, otherwise the turntable won't run.

Steph

Sorry, but I can't see any screw. Or are you refering to that nut underneath?
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Re: Thorens tp90 tonearm

Post by StephDale » 14 Nov 2019 20:11

Yours is already broken, it appears.

This shot I've just found online shows how the crack forms through the part if the screw is over-tightened:

http://up.picr.de/10188498dm.jpg

It's tricky to replace as you'll need to un-solder the tonearm wires from the circuit card, remove the shutter, find a new one and install it in the right position, before re-soldering the wires to the circuit card.

Steph

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Re: Thorens tp90 tonearm

Post by StephDale » 14 Nov 2019 20:17

One alternative would be to blank off the optical detector (perhaps with some scrap opaque plastic, card, or something similar), which would get the turntable running and arm to stay down. But, you'd lose the end of side shut off.

It would at least allow you to use the turntable and, if you find a shutter, you'd then be able to repair it.

Steph

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Re: Thorens tp90 tonearm

Post by babadockia » 14 Nov 2019 21:18

StephDale wrote:
14 Nov 2019 20:17
One alternative would be to blank off the optical detector (perhaps with some scrap opaque plastic, card, or something similar), which would get the turntable running and arm to stay down. But, you'd lose the end of side shut off.

It would at least allow you to use the turntable and, if you find a shutter, you'd then be able to repair it.

Steph
Thank you again! I incline more to the second alternative. Like I said my idea is to only lower the tonearm and to lock it in position or to change the tonearm with the one from 145, or an all new tonearm I have from Lenco, a custom made.
Thank you very much Sir, you've been very kind

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Re: Thorens tp90 tonearm

Post by StephDale » 15 Nov 2019 18:46

You're very welcome - I'm pleased we (sort of) solved the problem. If I were you, I'd stick with the TP90, if it's set up well it is a wonderful thing. Delicate in some ways (as you know with the shutter, and the cueing platforms can fail as well), but well worth the effort.

Steph

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Re: Thorens tp90 tonearm

Post by babadockia » 15 Nov 2019 20:12

StephDale wrote:
15 Nov 2019 18:46
You're very welcome - I'm pleased we (sort of) solved the problem. If I were you, I'd stick with the TP90, if it's set up well it is a wonderful thing. Delicate in some ways (as you know with the shutter, and the cueing platforms can fail as well), but well worth the effort.

Steph
It's a heavy arm, 17 grams. Wouldn't be difficult to find a good match?

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Re: Thorens tp90 tonearm

Post by StephDale » 15 Nov 2019 22:31

Not in my experience, although that probably reflects my taste in cartridges! Here's some I know work well: Audio Technica AT95E, VM95 series, VM520EB, OC9MLii, AT33SA, AT33MONO, Ortofon Kontrapunkt B and C, SPU Royal N. There are the odd other one or two that I've used with it too, including a Benz Glider SL, which for me was just too warm and cuddly in this combination.

If you're into moving coil cartridges with their typically lower compliance it's a great arm with that 17-18g effective mass: The pick for me on the TP90 is the AT33SA, which is a stunning combination but you need to be absolutely fastidious to get the best out of it.

There's also the Phonosophie counterweight for the TP90, which is very impressive in it's effect, but the price will make you wince. With that in place, you can use quite exotic cartridges (such as the Kontrapunkt C or SPU) if that's your thing. If you look on German forums you'll see the counterweight is considered almost essential, people are then using them happily with all sorts of cartridges.

Steph