Thorens TD 125 Mki - capacitor values

music box
varunbadola1974
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Re: Thorens TD 125 Mki - capacitor values

Post by varunbadola1974 » 22 Jul 2019 15:59

I took a few pictures of the PCB from my phone, which apparently are too large to be attached. But I can make out that the Film caps are bloated. Filter caps and others were changed recently so they look fine. I think I'll recap the complete board. Can the small resistors be left as it is? A friend suggested that I take off every thing and give the board a benzene or a white petrol wash. it seems that the last owner did not clean the board properly before installing the new caps.

varunbadola1974
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Re: Thorens TD 125 Mki - capacitor values

Post by varunbadola1974 » 22 Jul 2019 16:00

I took a few pictures of the PCB from my phone, which apparently are too large to be attached. But I can make out that the Film caps are bloated. Filter caps and others were changed recently so they look fine. I think I'll recap the complete board. Can the small resistors be left as it is? A friend suggested that I take off every thing and give the board a benzene or a white petrol wash. it seems that the last owner did not clean the board properly before installing the new caps.
Thanks
Varun

varunbadola1974
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Re: Thorens TD 125 Mki - capacitor values

Post by varunbadola1974 » 22 Jul 2019 19:11

IMG-20190722-WA0011.jpg
My PCB
(106.56 KiB) Downloaded 40 times


This seems to be from probably the first production lot. Looks different from the pictures posted on the previous page.

timmysteve
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Re: Thorens TD 125 Mki - capacitor values

Post by timmysteve » 10 Aug 2019 16:40

It's been three years since I started this thread. In the end I changed everything on the board apart from a few resistors and the transistors. I would make sure you have thoroughly taken apart and cleaned the speed selector switch and replace the other caps if you need to. If all else fails there is a seller on Ebay in the UK who has built a modern circuit board for the Mk1 that just replaces the old circuit board.

varunbadola1974
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Re: Thorens TD 125 Mki - capacitor values

Post by varunbadola1974 » 20 Aug 2019 08:52

Thank you so much for the reply. I thought the thread had gone dead. Yes I have cleaned the speed selector switch and the rest of the table. I checked the resistors and found that the value of a few has increased by a bit. One point, which should have had a resistor of 75k value, only had a 56k resistor. The same exact value of capacitors is also difficult to find. So I am given to understand that instead of a 2500uf cap, I can plant a 2200uf. The volts can be increased to 63V.
thanks
Varun

varunbadola1974
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Re: Thorens TD 125 Mki - capacitor values

Post by varunbadola1974 » 03 Oct 2019 09:45

Gentlemen,
I am stuck with transistors now. As BC147 is no longer manufactured, I read somewhere that BC547 is a drop in replacement for it on the Thorens 125 MK1 PC board. The manual does not say whether it is polar or bipolar. One online site has different models available such as BC547B, BC547BTA, BC547BTF, BC547CBU. Is there a difference in the mentioned types? Plus, all of these are bipolar. So am I suppose to put bipolar transistors on the PCB?
Thanks
Varun