Thorens tp90 tonearm

music box
babadockia
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Thorens tp90 tonearm

Post by babadockia » 08 Nov 2019 13:45

hello everybody!
I've just got myself a thorens td320 mk III kinda beat up: no belt, no headshell, the tonearm rest is a bit torn, no covers for the springs, you know minor s**t. I put a new belt, cleaned the spindle and the bearing, new oil (light sewing machine oil) and it's running smoothly. my problem is that the cueing doesn't lock the tonearm in the play position. I know, the player must be on but even though is on, the tonearm does not lock in the play position. you think with the headshell will it be working?
thank you kindly for any suggestion

StephDale
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Re: Thorens tp90 tonearm

Post by StephDale » 08 Nov 2019 17:56

Hmm, the headshell won't make difference to the cueing mechanism. With the motor running and the headshell positioned over the lead-in groove, turning the cueing lever should cause the arm to drop and latch in the running position. When the arm has tracked the way to the run-out, the optical shutter underneath the tonearm should open, there's a metallic 'clunk' sound the arm lifts off the record and the player stops.

I'd get that headshell (which might cost around £100-150 these days) and have a try, if it still doesn't work then it's worth looking underneath at the position of the shutter and to see if the light under the tonearm is functioning. If all else fails you'll have to revert to the service manual here on VE and see what's going on. I have had to use the test procedures a couple of times and they have led me to diagnose the fault in each case.

Steph

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Re: Thorens tp90 tonearm

Post by babadockia » 08 Nov 2019 18:01

StephDale wrote:
08 Nov 2019 17:56
Hmm, the headshell won't make difference to the cueing mechanism. With the motor running and the headshell positioned over the lead-in groove, turning the cueing lever should cause the arm to drop and latch in the running position. When the arm has tracked the way to the run-out, the optical shutter underneath the tonearm should open, there's a metallic 'clunk' sound the arm lifts off the record and the player stops.

I'd get that headshell (which might cost around £100-150 these days) and have a try, if it still doesn't work then it's worth looking underneath at the position of the shutter and to see if the light under the tonearm is functioning. If all else fails you'll have to revert to the service manual here on VE and see what's going on. I have had to use the test procedures a couple of times and they have led me to diagnose the fault in each case.

Steph
Thank you for the reply. I tried to look for this kind of problem but I couldn’t find this specific one

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Re: Thorens tp90 tonearm

Post by StephDale » 08 Nov 2019 18:35

Hehe, fair point! You need this one; https://www.vinylengine.com/ve_download ... _en_de.pdf all the TD320-series turntables use the same controller board.

The TD2001 also uses the same driver anh TP90 tonearm, so that manual is useful too: https://www.vinylengine.com/ve_download ... _en_de.pdf

Steph
Last edited by StephDale on 08 Nov 2019 18:38, edited 1 time in total.

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Re: Thorens tp90 tonearm

Post by babadockia » 08 Nov 2019 18:38

Thank you again, but I already studied it. Controller board you’re saying? That complicated? Both my dual and my Lenco are a just a walk in the park comparing to that s*^t.

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Re: Thorens tp90 tonearm

Post by StephDale » 08 Nov 2019 18:47

If you think it's s* they why are you using it? :D

It was a pretty sophisticated electronic design for its time, but they're easy to test and tend to be reliable once set up. Personally, I reckon it's worth sticking with; both the basic chassis and tonearm are well regarded. The problems you're describing are most likely related to the optical switch under the tonearm; it may be as simple as plugging it back in again.

As a start, here's a pic of the underside of a TD2001 that's recently passed across my bench, the position of the tonearm and shut off components should match your TD320. It's shown here with the arm in the rest. I don't have any equivalent pictures of a TD320, but although the spring positions and sub chassis differ, the layout is broadly the same.
20190322_155931.jpg
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Steph

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Re: Thorens tp90 tonearm

Post by babadockia » 08 Nov 2019 19:44

It was just a joke seeing it too complicated for my simple mind and I am not well prepared to fix electronic stuff. Anything mechanical and simple, no problem but with your or somebody else’s help maybe I will be able to have it done.

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Re: Thorens tp90 tonearm

Post by babadockia » 08 Nov 2019 23:41

StephDale wrote:
08 Nov 2019 18:47
If you think it's s* they why are you using it? :D

It was a pretty sophisticated electronic design for its time, but they're easy to test and tend to be reliable once set up. Personally, I reckon it's worth sticking with; both the basic chassis and tonearm are well regarded. The problems you're describing are most likely related to the optical switch under the tonearm; it may be as simple as plugging it back in again.

As a start, here's a pic of the underside of a TD2001 that's recently passed across my bench, the position of the tonearm and shut off components should match your TD320. It's shown here with the arm in the rest. I don't have any equivalent pictures of a TD320, but although the spring positions and sub chassis differ, the layout is broadly the same.

20190322_155931.jpg

Steph
I once had a td 318 but I gave it away because it had some very nasty speed fluctuations and I wasn't able to eliminate them, this is how I know about that "klang" noise when the tonearm is engaged. Sorry Steph, but I was thinking more about a mechanical problem given the nature of that particular sound

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Re: Thorens tp90 tonearm

Post by StephDale » 09 Nov 2019 09:33

The clunk is just the solenoid (bottom left in my photo), its operation is what raises the tonearm, you can see the length of Bowden cable snaking up to the tonearm itself, where it clips into the bottom of the arm lift.

Steph

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Re: Thorens tp90 tonearm

Post by babadockia » 09 Nov 2019 09:50

StephDale wrote:
09 Nov 2019 09:33
The clunk is just the solenoid (bottom left in my photo), its operation is what raises the tonearm, you can see the length of Bowden cable snaking up to the tonearm itself, where it clips into the bottom of the arm lift.

Steph

Thank you again. I will open it up again tomorrow and I will definitely bombard you with questions. I did clean the bearing, the spindle, the pulley, I put a new original thorens belt and it spins constantly and quietly with the same speed. A bit higher, but it is adjustable. If I could fix that cueing problem, me is happy.
Thank you again.
PS I really have no idea what could be the cause

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Re: Thorens tp90 tonearm

Post by babadockia » 13 Nov 2019 11:09

StephDale wrote:
09 Nov 2019 09:33
The clunk is just the solenoid (bottom left in my photo), its operation is what raises the tonearm, you can see the length of Bowden cable snaking up to the tonearm itself, where it clips into the bottom of the arm lift.

Steph
I've tried to PM you but I can't attach pictures. Could you tell me please what is wrong, because to my untrained and poor eyes everything seems to be in its place
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babadockia
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Re: Thorens tp90 tonearm

Post by babadockia » 13 Nov 2019 11:11

Here some more
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StephDale
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Re: Thorens tp90 tonearm

Post by StephDale » 13 Nov 2019 20:36

The tonearm shutter is waaaaay out of place, assuming you photographed it with the tonearm In the rest. Compare the position of the shutter in the first three photos in your last post with the photo I posted.

Carefully release the screw on the side of the shutter, turn the shutter to blank the light source and tighten the screw again. Careful though; if you over-tighten the screw you can break the shutter.

The position of the shutter will need fine-tuning to get the end of side shut off to work properly, but that's just trial-and-error, once you've got the basics working.

Incidentally, it all looks nice and clean and tidy in there, which is great. It's certainly better than a couple of the TD320 I've dealt with over the years.

Steph

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Re: Thorens tp90 tonearm

Post by babadockia » 13 Nov 2019 21:33

StephDale wrote:
13 Nov 2019 20:36
The tonearm shutter is waaaaay out of place, assuming you photographed it with the tonearm In the rest. Compare the position of the shutter in the first three photos in your last post with the photo I posted.

Carefully release the screw on the side of the shutter, turn the shutter to blank the light source and tighten the screw again. Careful though; if you over-tighten the screw you can break the shutter.

The position of the shutter will need fine-tuning to get the end of side shut off to work properly, but that's just trial-and-error, once you've got the basics working.

Incidentally, it all looks nice and clean and tidy in there, which is great. It's certainly better than a couple of the TD320 I've dealt with over the years.

Steph
Thank you bunch for the answer but now I'm asking: which one is the shutter?

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Re: Thorens tp90 tonearm

Post by StephDale » 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

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