THORENS TD125 (ORIGINAL Mk1) 3-SPEED REPLACEMENT CONTROL BOARD

NOTE: Although it says 'used' this is a brand new board assembled by the seller and connected to a Thorens turntable for testing and adjustment.

NOTE - THERE IS A 3-WEEK LEAD TIME FOR MAKING THE BOARDS

UPDATE - New features of the Mk1 boards
My revised Mk1 board is based on the more advanced Mk2 design using op amps, giving improved waveforms and more stable speeds. It now has chassis-mounted transistors to ensure adequate cooling. The original Mk1 board and the 2 old transistors are removed from the chassis and the new board together with the attached transistors are mounted in their place. The 4 new transistors are mounted on a separate mini PCB wired to the main board and the 4 are bolted onto the chassis using the 4 bolt holes vacated by the 2 old transistors. The chassis provides an excellent heat sink for the new transistors.

This is a brand-new 3-SPEED circuit board for the original Thorens TD125 (MkI) which gives 16,33+45rpm speeds. The speed-change slider and fine-speed adjustment on the facia of the turntable work the same as the original. I make a different version of the board for the Mk2.

The boards are provided as a 'plug-and-play' replacement for the old board (although 'screw on, solder and play' would be more accurate!)

I've owned a number of TD125s over the years and they have nearly all had temperamental speed control. This is not too surprising because the turntables are now around 50-years-old! The electrolytic capacitors, transistors, sliders, lamp, op-amps, solder connections and printed circuit board can all give trouble but just about anything on the board can fail, making fault-finding tricky and frustrating.

I developed the new speed-board as a labour of love to get my current cranky old Thorens working. Its circuit board had multiple problems so I decided to design a complete replacement for assembly in my own workshop. I originally developed the board for the TD125 Mk2 but I have since modifed the design to work with the Mk1 which has a different motor and transformer.

Producing the new board was long process partly because of the completely redesigned switching system. The new mechanism uses microswitches in place of the troublesome sliding metal contacts. This means none of the old board has to be salvaged for the new board.

It is a drop-in replacement for the old board and is bolted in the same place as the original board. The speed control lever works the same as does the fine speed-adjustment knob. It is a very careful re-design of the original board. It uses the same Wein bridge oscillator circuit but the circuit board has been reconfigured with updated components. For instance, the new smd transistors are superior and reliable compared to the originals which are easy to overload and damage. 

The re-designed printed-circuit boards are professionally fabricated.

The structural components used with the board were very carefully designed using CAD and are professionally printed using SLS technology. 

The new owner has to unsolder the 8 wires attached to the original board and resolder them to the new board. 

Full instructions (with photos) sent by email.

What you get is a fully working speed control board which has been connected up to one of my own turntables and adjusted. Only minor further tweaking should be needed in another TD125.

A short video of the turntable running at 78rpm can be found here: https://youtu.be/DWBg6KjEtYo

Recent feedback from buyers of the speed board:

• ‘An excellent transaction, with a highly recommended eBayer. Thanks very much.’
• ‘Very high quality. Working perfectly.’
• ‘Excellent high quality board. Good instructions, fantastic support. Thank you!’
• ‘Excellent item and service. Many thanks.’
• 'Your initial set up was spot on as I needed to make no further adjustments to speed other than a slight nudge to the above deck speed control. Speed remained dead on all weekend with no tweaks necessary.Thanks again for making this board available. It is definitely a fine replacement for the original. If I ever come across anyone needing a board repair for their Thorens 125, I will highly recommend they obtain one of these.'

Buy with confidence - see my feedback!

Please message me about shipping costs if you live abroad.