Thorens TD-320 MkII issue

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jeff101352
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Thorens TD-320 MkII issue

Post by jeff101352 » 16 Dec 2019 21:03

Thorens TD-320 MkII issue

Upon recommendation that there was a Thorens section, I am posting this edited question (previously posted in the main/general VE category), seeking help on my newly acquired 320 MkII.

I just purchased a Thorens TD-320 MKII - AT OC9 III cartridge; it was recently restored beautifully, but was damaged during shipping to me from overseas). Love the sound.

I have the Thorens adjusted and setup, and all is well except the auto shutoff is not working properly. I've read a lot of forum and blog discussion on this topic, and have tried the proposed answers.

My issue is that I have it adjusted so that it will click off when the TA reaches the lead-out grooves. It was finicky to adjust and I spent several hours getting that adjustment correct; moving the plastic piece inside the TT (under the TA) very slightly until positioned just right.

The problem is that it will only shutoff with the TA in the up position. When the record is playing (down position), it does not activate the shutoff mechanism.

That leads me to believe it is a height issue. ??
So I tried adjusting the VTA all the way down (no luck); and very high (also no luck).
I also opened the TT and looked at adjusting the height of the plastic tab (inside of the TT) that is used to rotate the IR mechanism for shutoff. I really didn't see how I could raise or lower the plastic piece, and didn't want to force it or break it.

From my reading of the manual, and other web info, I believe there is a voltage component to the auto shutoff. But I am not sure if that is an issue in my case, since the unit does shutoff when it reaches the lead-out grooves - in the up position. But I just don't know enough to guess intelligently.

Any Thorens expert advice would be greatly appreciated.

Thanks ALL
Jeff
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StephDale
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Re: Thorens TD-320 MkII issue

Post by StephDale » 16 Dec 2019 22:06

Hi Jeff,

I saw your original request, which seemed entirely reasonable. I'm still needing a little time to check the service guide to see what tests we can apply to understand what's going on: I was hoping someone would have the answer, but it appears your problem isn't something we've come across before.

Just wondering where you are, geographically?

More soon, I hope,

Steph

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Re: Thorens TD-320 MkII issue

Post by jeff101352 » 16 Dec 2019 23:51

Hi Steph
Thanks for your reply. So many good knowledgeable folks on this site; and I'm just a newbie.
I'm in Fla, and there aren't many (any?) Thorens expert service folks close by (at least that I can find).

The seller / restorer is in Denmark, and has been quite helpful - but emails can only do so much. He has never seen this particular issue before. I sent him videos of the TT stopping when the TA was over the leadout grooves in the up position; and another where it shows the TT just 'running on' when playing. Also, when the device is turned off, it does stop the motor and raises the TA. I just don't have a clue....

I also received a nice response from the Thorens service manager in Germany; but again he commented 'that it is difficult to diagnose without having the TT in front of him.' He did say that it was not a height issue, and seemed to think it could be related to a voltage issue... But my seller says if it works in the up position, then likely not a voltage issue, and not broken.
Jeff
ps- Although frustrating, I do really enjoy learning how it works. Neat new hobby.

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Re: Thorens TD-320 MkII issue

Post by jeff101352 » 24 Jan 2020 20:13

Thought I'd try to resurrect this query since no responses.
Has anyone had this particular experience with the auto shutoff feature?

And since my seller was from overseas (not many Thorens 320 models for sale over here / which I wanted...), then it doesn't make sense to ship back and forth for him to repair; and there seem to be NO Thorens service experts in Florida.

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Re: Thorens TD-320 MkII issue

Post by sausagecreature » 29 Jan 2020 22:45

Hi Jeff,
I have a 321, so no auto shut off so I am not familiar with this. However, if the seller was genuinely unaware of any such behaviour then I can think of two things that I might be thinking about...At least until Steph or someone else comes up with something else to try...so for me, firstly I would be wondering if something happened in transit to cause this.

Secondly-now that the turntable is now installed in a different place - did you go through all the correct set up process with it?

When I first got my 321 home I found the belt would jump off, and I found myself thinking "Did the seller not know about this, or did it not happen to him?"...After I followed the steps in the manual and also worked through all the advice offered by this guy on Youtube.
https://www.youtube.com/watch?v=WM-aIDwfrhc

Once I had followed all the steps, the TT has behaved faultlessly since. I thought the video above was really well done, very helpful and easy to watch and to follow.

Sorry if I am suggesting things you have already tried. I know our issues are very different, but what I learned was how important it is to level and set up correctly. This is not the first time I have suggested such an approach in response to a post...I hope I am not starting to sound like a scratched record here on VE.

Good luck!
Mark

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Re: Thorens TD-320 MkII issue

Post by StephDale » 30 Jan 2020 00:30

Jeff,
Sorry for not replying, I 'lost' the thread. Not for the first time, some might suggest...

I can't reproduce the fault on my TD2001, which has the same guts as your 320. I wonder whether you've got a loose connection on one of the components or connectors which plug into the main control board. My best guess would be something associated with the arm raise/lower lever...

A couple of quick tests might make the penny drop a little faster:
With the tonearm up, the shut-off works so you'll no doubt recognise the clonk sound when it does so. With the tonearm down, do you get the clonk sound when the arm reaches the end of the side?
The arm collar has two grub screws to adjust the height of the arm, one at the back, one on the right hand side, both take a small metric Allen key. Have you done anything with those screws? And, is the arm horizontal and parallel with the record surface when playing?
Is the length of Bowden cable in place between the raise/lower knob and the lever underneath the tonearm.
Is the arm collar still screwed up tight to the armboard, or does the arm assembly move when the arm itself is clipped into its rest?

It might just give me an idea; well, I'm hoping so!

Steph

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Re: Thorens TD-320 MkII issue

Post by sausagecreature » 30 Jan 2020 08:01

Where would we all be without you Steph? :)

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Re: Thorens TD-320 MkII issue

Post by StephDale » 30 Jan 2020 22:46

sausagecreature wrote:
30 Jan 2020 08:01
Where would we all be without you Steph? :)
Ha! We haven't fixed it yet, Mark, and I'll need a much better idea of what's going on before I'll be confident we can.

Steph

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Re: Thorens TD-320 MkII issue

Post by jeff101352 » 30 Jan 2020 23:35

Hey Mark and Steph.
First, thank you both for reading and replying. And Steph, I appreciate your efforts to duplicate my problem. I know it is time consuming. I did actually watch the setup video Mark posted, several months ago. I was a newbie then, and am now 'slightly more knowledgeable' after so much web search.

The shipping was very unkind to the TT. The dust cover was smashed (I had to order a new one - and JMK Displays, in the state's, made a beautiful one for me -http://www.jmkdisplays.com/turntablecovers.html; pic attached).

And the suspension screws / wires were broken in 2 places. I had to order new ones from Switzerland, wait a month for them to arrive and, then, figure out how to install them. I finally did, and the suspension is properly set up now; and evenly balanced with the weight of the platter & subplatter, etc. And I adjusted the VTA and cartridge alignment. All good, and sounds really great. The only issue is the shutoff, which I prefer to have working; but will live without if it can't be fixed. Still love the TT, a classic.

From Steph:
With the tonearm up, the shut-off works so you'll no doubt recognise the clonk sound when it does so.
With the tonearm down, do you get the clonk sound when the arm reaches the end of the side?
[No clonk or anything when the record is playing and TA down... The TT just keeps spinning. I have short videos of
this, but can't seem to attach movies to this thread. When the TA is up, and adjusted properly, the motor shuts off
and the TA would raise / but is already in the up position. With record playing, I can turn the switch to off, and the
motor stops and TA raises.]
The arm collar has two grub screws to adjust the height of the arm, one at the back, one on the right hand side, both take a small metric Allen key. Have you done anything with those screws? And, is the arm horizontal and parallel with the record surface when playing?
[I did loosen those screws to adjust the TA height for my cartridge adjustment. While playing, the TA is horizontal
and parallel to the record, which I think is the correct height adjustment.]
Is the length of Bowden cable in place between the raise/lower knob and the lever underneath the tonearm.
[I don't know what the Bowden cable is. Attached are 2 pictures of the underside / inside of the TT, while the TA is in
the cradle / neutral position. Does this show what you are referencing?]
Is the arm collar still screwed up tight to the armboard, or does the arm assembly move when the arm itself is clipped into its rest? [Yes, tight.]

As stated in the earlier post, the current Thorens service manager was very helpful with advice and thought it was a potential electrical component gone bad. But my seller disagrees, and says that if it shuts off in the TA up position, then it is not an electrical issue, but an adjustment issue. ??? I don't know.

And again, many thanks for your comments and helpful efforts.
Jeff
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jeff101352
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Re: Thorens TD-320 MkII issue

Post by jeff101352 » 03 Feb 2020 23:04

Steph and Mark

A follow-up. I finally found a repair tech for vintage equipment, about 2 hours from my home (Ken- at Audiotronics in Melbourne; in case any Fla folks read this and are looking for an expert). I am not sure how much experience he had with Thorens, but know he had some. He specializes in fixing vintage electronics and audio equipment. I was able to provide him with the owner's manual and schematics. He seemed very knowledgeable at the outset; and proved it at the end. I was very impressed with his knowledge and skill, and professionalism.

The bottom line - the problem was that the speed detector on the auto shutoff needed adjustment. Not a mechanical adjustment with the plastic piece inside the plinth, but an electronic adjustment of the Ohms output on the speed indicator. Ken said he initially adjusted the Ohms up from 40 to 60, then incrementally until about 100 Ohms - at which point the auto shutoff worked while the record was playing. I would never have been able to figure this out or make the correct adjustments, but Ken figured it out quickly.

When asked why it would shutoff with the tonearm in the up position while I advanced the tonearm toward the record center, I was told it was because I moved it fast enough to actuate the shutoff mechanism; while it was too slow moving over the playing of the record to actuate the speed sensor.

This result is consistent with the advice of the Thorens service manager (that it was likely an electronics issue dealing with the speed increase at the lead-out grooves of the record); as opposed to the contrary advice from the seller that it was simply a mechanical adjustment of the plastic piece.

My current service tech also indicated that the speed detector part (not sure what to call it) will slow down or deteriorate over time, and mine may need replacement at some point, but maybe not... (he said it was a common part readily available if needed in the future).

So I finally got the 320 MKII up and fully functional. I just wanted to pass on this info in case you were still following my query.

Thx gain for your assistance.
Regards
Jeff
PS- If I misspoke or misstated any technical info above, I am sure it was my mistake and probably an inaccurate recollection of Ken's explanation of the problem and correction. LOL

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Re: Thorens TD-320 MkII issue

Post by sausagecreature » 23 Feb 2020 11:21

jeff101352 wrote:
03 Feb 2020 23:04
My current service tech also indicated that the speed detector part (not sure what to call it) will slow down or deteriorate over time, and mine may need replacement at some point, but maybe not... (he said it was a common part readily available if needed in the future).

-- I can believe that all things considered. Although I would not have had a sausage that it was the cause until someone told me.

Excellent finding/conclusion. Very pleased to hear it has all worked out for the best. I imagine it wasn't expensive either.

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