thorens 150 skeletal deck MK2

[john & Jake]

Final incarnation just waiting for power supply parts.
Much reduced mass using more air than foam.
1mm epoxy resin, foam,0.5mm carbon fibre sandwich.
6mm thick alloy bar embedded in the foam to directly couple the arm to spindle bearing.
Rega arm, Nagoaka MP200 cart

 

[B-Ark-610873]

How is the bearing held? I assume you pressed it out of the original sheet metal sub-chassis but is it screwed to the chassis?

 

[Mr_Sukebe]

Very smart!!!

 

[john & Jake]

Hi, with the plinth being foam, fixings are limited so I've bonded it through an 18.5 mm hole in the 6mm thick alloy plate that is bonded inside the foam running from the bearing to the arm. The arm is fitted through a 23mm hole.
Bonded with megabond mb60 epoxy.
I'm fitting a linn motor this evening as the 150 motor has decided to run backwards unless helped in the right direction.
A common fault apparently.

 

[john & Jake]

Thanks mr Sukebe. I am pleased how it has turned out as I dont have access to fancy cutting gear. All done with a jigsaw and sander.

 

[Mr_Sukebe]

Thanks mr Sukebe. I am pleased how it has turned out as I dont have access to fancy cutting gear. All done with a jigsaw and sander.

I'm hopeless at DIY, so that's a big wow from me.

 

[Craig B]

I'm fitting a linn motor this evening as the 150 motor has decided to run backwards unless helped in the right direction.
A common fault apparently.

Running backwards will be down to the 0.33uF phase capacitor having gone off.

Suggest replacing this with a same value film type for improved reliability.

 

[stevec67]

Nice. You can fix the motor by building a diy Geddon and this will have the right phase shift cap that will make the motor run as intended. By the way just swapping the motor won't work, it's the control board that's at fault. The Linn motor will need a Basik or Valhalla or similar power supply (control) board, or the thorens one once repaired.

 

[Craig B]

You'd be needing a 16-pole AC motor to match the Thorens original if using the Thorens drive pulley and platters. The reason being that 16-pole rotates at 375rpm on 50Hz mains, hence the Thorens having a circa 14mm diameter drive pulley compared to Linn having 21mm diameter fitted to its 250rpm 24-pole motor.

As to using a Linn motor and pulley with Thorens platters, although the sub-platters are similar in size, they are not exact, with Thorens being a few mm smaller, meaning that platter rpm will be slow (circa 32.2rpm). You may be able to compensate by tilting the motor.

A lot of faff compared to fitting a fresh 0.33uF cap for the existing Thorens motor, though.

 

[john & Jake]

Hi Steve, linn Basik power supply arriving in the morning courtesy of lp12 bits.

 

[john & Jake]

Hi Craig, comparing my linn platter to the thorens I make the thorens a couple of mm smaller. The way to make it work is to tilt the motor away from the platter enough to make the belt run low down on the motor pulley.
I will be able to measure the speed tomorrow.

 

[RJohan]

Cooool!

Hmmmm, makes think of doing something with my LP12...

 

[john & Jake]

Hi all, fitted a Linn Basik supply. belt is running about 4mm from the bottom of the pulley.
Here's a screenshot of a speed app.
I'll do some fine adjustment but happy at the moment.
Time for some more listening with this motor but I was happy with the improvement over the Linn before it decided to reverse.

 

[chartz]

Could you find a clutch pulley? Much better if you don’t want to replace the belt every year

 

[john & Jake]

Hi chartz, looked into that when my linn groaned on startup but couldn't find one.

 

[Craig B]

Hi all, fitted a Linn Basik supply. belt is running about 4mm from the bottom of the pulley.
Here's a screenshot of a speed app.
I'll do some fine adjustment but happy at the moment.
Time for some more listening with this motor but I was happy with the improvement over the Linn before it decided to reverse.

Just to be clear, John, is this with a Linn sourced 24-pole motor/50Hz pulley and Basik supply fitted?

BTW, meant to say 'excellent work' earlier.

 

[john & Jake]

Yes standard 50hz lp12 motor with the early lp12 supply known as Basik I think.

 

[john & Jake]

Thank you Craig, I am pleased how it has turned out for such a simple arrangement.

 

[Craig B]

Yes standard 50hz lp12 motor with the early lp12 supply known as Basik I think.

Depending upon how early, it may have become known as 'Basik' retroactively.

Naked PCB with 4 x caps on?

First 'Basik' supply, 240V or 120V (the latter bypassing the dropper resistor), motor still required either 50Hz or 60Hz pulley depending upon market. Came with the black rocker switch.

 

[john & Jake]

Yes Craig its the naked one.