Late-production HMV portable governors

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Schmaltz
Victor I
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Late-production HMV portable governors

Post by Schmaltz »

Interesting issue I ran into when I purchased an apparently NOS governor made in the post-war period, made for the acoustic portable which was still using the traditional Victrola motor (and was a perfect fit in the older motor). The original governor in this unit had a pronounced flutter that adjustment could not cure, but no speed fluctuation. This new one has no flutter, but the speed will randomly slow down, speed up slightly, then settle back to normal.

To make the issue clearer: this is not a slowdown on louder notes. I've heard that before, and in those cases the speed does not increase above normal after the slowdown: it simply comes back up to normal. In this case, there is a change on both sides of normal, from slow to fast, then back to 78.

The post-war governor was made differently that the earlier ones. Some of you may have seen this: it has "tabbed" ends on the governor springs rather than screws and washers. The pot metal governor body holds the tabs in place with notches, and a wire around the governor body keeps the springs from flying out.

What this amounts to is that the governor can "twist" slightly during play. This momentarily has the effect of shortening the governor springs and pushes the governor plate further in. The turntable slows down, then speeds up again, then settles back to regular speed as equilibrium is established. Earlier governors with the springs screwed into place have no tortion twist so this does not happen.

ADDENDUM: after further thought on this, it occurred to me that fluctuations in driving force would be a factor here. Whatever the tendencies of the governor to fluctuate in speed, it would be reacting to changes in driving force, like the kind where there is a bit of grit in between gear teeth. So I turned the motorboard upside down again and went to work. I used a small screwdriver to dig out every bit of old grease I could find in the teeth of both the driving gear and the spindle worm. Most teeth were clean, but enough were hanging on to bits of very old hard grease for this to be a potential problem. Re-greased the gears, put it back together for a test, and it is much improved. The speed fluctuation still happens now and then, but it is much less frequent and much less severe. I'm listening to "Show Me the Way" by Coon-Sanders on it right now, a very late acoustic, and the speed is rock solid.
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gramophoneshane
Victor VI
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Joined: Wed Jan 07, 2009 3:21 pm

Re: Late-production HMV portable governors

Post by gramophoneshane »

I've actually never come across these sorts of governors on an HMV wind-up motor before. The lastest example of an HMV motor I have is from 1953, but it retains the screw on springs.
I've never pulled down an HMV electric motor, so I dont know what set-up these used.
The only motors I have found with the slotted governor springs & retaining wire, were in Garrard electric motors.
I do have two wind-up motors with this type of governor, but they dont have the wire retainer. One is a Garrard No.30 single spring motor, and the other came in my new "HMV crapophone" which uses a cheap copy of the Garrard no.30 motor.
One thing all these governors have had in common was the shape of the weights, and that the weights are on the underside of the spring, rather than on the outside as is usual on other governors.
Attachments
garrard 30 002.JPG

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