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Question about Gramophone size of spring power

Posted: Fri Sep 03, 2021 2:12 am
by showgolf
Hello from Thailand again

My uncle give me The Crowd Gramophone and It’s a Thorens 2 spring power motor. When I open a spring cover a spring is edit between 2 size in a line. On head about 10 cm long is wide 2.5 cm and wide 3.2 cm until end about 400 cm long.
I tried to make a new spring power is 2.5 cm wide , 0.5 cm thick and 350 cm long but when I test the power by put a sound box to record and It’s stop . after that I tried to adjust a governor and test an rpm by mobile application an highest rpm I can make is 54 (not adjust speed pin). Should I make a new spring? What a real spring size of this Thorens motor (see photo)?

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Re: Question about Gramophone size of spring power

Posted: Fri Sep 03, 2021 6:08 am
by Marco Gilardetti
Personally, I've never seen a gramophone spring that doesn't have the same size at the head and at the tail. The spring pictured on the left also looks heavily deformed. In general, I would suggest replacing both with appropriate new springs.

That said, however, they also don't look terrible to the point of not being able to spin the turntable at 78 RPM "freely", with no drag and no load. It looks that those springs should be good enough to reach 78 RPM and above with no problems, by tweaking the governor. I would then assume that there are also other issues, like perhaps a not properly lubricated governor shaft / pad.