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Thorens TD125 Mk II- totally dead
Thorens TD125 Mk II- totally dead
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Old 31st October 2007, 01:20 PM   #1
Ken(Toronto) is offline Ken(Toronto)  Canada
diyAudio Member
Join Date: Oct 2007
Default Thorens TD125 Mk II- totally dead

Need Help!

I turned my Thorens on after 10 years sitting in the basement (never used it after I moved 10 years ago); and it won't turn.

Found the service manual on the Net.

Found the following:

Phase I voltage measurements: between RT and GE, 3.8V AC regardless whether on 16, 33, or 45 RPM position

Phase II voltage measurements: between BL and GE, 0 volts regardless whether on 16, 33, or 45 position.

Doe this mean one of the Ua709 op amps is dead? If so, which one?

Does anyone know the theory of the op amp operation? does each op amp generate 1/2 of the voltage required by the motor? Is each op amp a Wien Bridge oscillator?

Also, should I change all the capacitors on the board, or just the two big electrolytics on the power supply (1000uF 25V)?

Last question: where can I buy a 709 op amp in Toronto, Ontario, Canada?


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Old 31st October 2007, 01:25 PM   #2
Mark Kelly is offline Mark Kelly  Australia
diyAudio Member
Join Date: Feb 2006
Location: Willy, VIC
Try here:

A Page on TD125 drives

Any further questions just ask.
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