Sonora Governor Parts/Adjustment

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Frogsong
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Sonora Governor Parts/Adjustment

Post by Frogsong »

Hello,

I am completely new to these machines but I am a mechanical engineer and love tinkering. I recently received a Sonora Phonograph from my wife's family. Somewhere along the line, somebody made some repairs to the governor and it was a little out of whack. Luckily the weights are original, most of the screws are the same, but the spring steel strip that holds the weight had snapped at one of the screw holes and is barely hanging on by the fastener and one of the strips was replace all together. All the strips are a little bend out of shape compared to photos I have seen online (Attached) of the same setup. The Sonora plays but the it runs away on me as far as RPMs.

Can anyone explain to me how to adjust the governor along with the speed control friction pad? Any descriptions on how to adjust this setup would be really helpful, so far trial and error is all I can do.

Does anyone know where to find more of the type of spring steel used?

Thanks!
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Photo Found Online
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Lucius1958
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Re: Sonora Governor Parts/Adjustment

Post by Lucius1958 »

The important thing about governor springs is that they should all be identically matched: if you replace one, you should replace them all. Check with the suppliers mentioned in the "Links" thread, to see if they have any replacements suitable for a Sonora.

In a pinch, Eric Reiss suggests (in his Compleat Talking Machine - an invaluable basic book for collectors and restorers), that you can fabricate springs out of feeler gauge stock of the correct thickness. The holes would have to be punched instead of drilled, though, owing to the hardness of the stock.

The point is to have a perfectly balanced governor, to avoid flutter or other variations in speed. I hope this is helpful.

BTW, what model Sonora is it? Inquiring minds want to know. ;)

Bill

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Marco Gilardetti
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Re: Sonora Governor Parts/Adjustment

Post by Marco Gilardetti »

As a further note, keep in mind that should the replacement springs be too hard or too soft, the regulator may fall out of the range for which it was engineered, that is it will let the motor run too slow even at full throttle, or countrarywise too fast under all conditions and nearly impossible to adjust.

Specific replacement governor springs are available for common machines, and ideally you should purchase spares specifially made for Sonoras and already tested by others. Should this be impossible and should you have to buy generic parts matching the length/width of the damaged springs, if feasible at all you should care to purchase multiple sets of different thickness/hardness, and then see by trial & error which seems to match best with the speed control of your gramophone. The same, of course, in case you're going to try and craft the parts you need from scratch.

Frogsong
Victor Jr
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Personal Text: Aircraft Engineer, Phonograph Greenhorn

Re: Sonora Governor Parts/Adjustment

Post by Frogsong »

Thank you both for the advice! I have a Sonora Nocturne. I am also missing the front decorative "grill" on mine, I wonder if I can find a replacement or make a new one.

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