Disc Graphophone runs unevenly...

[De Soto Frank]

I am trying to sort-out my "new" Graphophone "Imperial" model BJ.

Last night I re-rubbered the Analyzing soundbox, it sounds great ! ( Thanks for the tips, Harvey ! )


But the motor runs unsteady.

Here's the symptoms:

Wind it fully, it plays through 3 sides of ten inch discs, but no more.

As it plays the speed fluctuates... slows-down slightly, speeds-up slightly. I've been trying to quantify it, but the best I can do is in musical terms...

Playing a 12" Columbia Disc, Waltzes from "The Count of Luxembourg" ( Franz Lehar ), the tempo is approximately quarter-note = 192 beats / minute or dotted half-note = 84 beats / minute ( "one beat to the bar" ). While the disc is playing, the music will slow-down slightly for about 3 bars, then gradually speed-up for about 4 bars, and repeat the cycle, through the entire disc. The cycle is pretty consistent.

The behavior is similar with other discs ( mostly 10-inch Victor and Regal this morning ). Even as the spring is running-down, this cycling still occurs, though the time to complete the cycle may be a little longer as the spring loses its oomph.

As for "how much" speed variation, I would say slightly less than ½-step in pitch variation between the high and low ends of cycle. ( the distance between adjacent black key and white keys on a piano or organ ). Enough to be noticeable and a bit frustrating.

This particular machine seems to be a very early example of the BJ: the winding crank is on the left-side, the speed-control / brake plunger is in the back. The reproducer is the Columbia Analyzing, but with a thumbscrew instead of the spring-loaded clamp. ( Latest patent-date behind the mica is Jul, 25, 05 ). The motor is a two-spring with a two-weight governor ( lead "lozenge" weights ).

Based on what I've been able to decipher from Baumbach's Columbia Phonograph Companion Vol II [ disc machines ], this motor is likely the same as the second-style AH front-mount machine, introduced in 1904.

It almost seems to me that there is a "binding" or "tightness" somewhere in the power train, as opposed to a governor issue ?


Has anyone run-into this with early Disc Graphophones ? This is my first experience with one, and I'd rather ask a lot of questions before plunging-into it with tools and invective...

Would appreciate any thoughts / suggestions from Disc Graphophone veterans...

Thanks !



Frank

[phonogfp]

It sounds like mainsprings to me. I suggest both mainsprings be removed, cleaned, regreased, and reinstalled.

It's a dirty job, and if you've never worked on those Columbia tabbed spring barrels before, be sure you scratch a mark adjacent to a tab and one on the tab itself so you can realign them later.

I'd recommend simply sending the spring barrel assembly to Ron Sitko and have him do the honors. He's reasonable and quick.

In addition, the mainsprings may need replacement. If so, they'll be in the right place at the right time!

George P.

[rizbone]

If it is repeating it might be a gear with a bad spot on it. You may want to see if one of them has a period of rotation that approximates the cycle of fast and slow.

[Phonofreak]

I had a problem similar with my Columbia front mount AJ second model. It was running uneven. What the problem turned out to be was the spindle was bent, and the spindle gear, both the brass and fiber gear had some damaged teeth. They were so minute, I couldn't see them. I used a magnifying glass to see the imperfections. I took the spindle and gear off of a spare motor that I had. Problem solved. Another point to check is the Governor. The governor is held by plates. Make sure the plates are properly aligned. Check to make sure the flange slides. That's important so the governor runs at proper speed.
Harvey Kravitz

[brianu]

it sounds to me as well like it could be a problem with a fiber gear being worn, the one on the spindle... yours is fiber, correct? I had this issue a while back with a worn fiber gear in a cameraphone I used to own. I noticed as well when you were playing this at the show that the turntable was not totally flat when spinning, so the spindle as well may be bent.

brian

[MicaMonster]

Here is what I believe is happening. The friction pads on the governor yoke have become soft and spongy. When the mainsprings are under full tension, there is sufficient torque to keep the friction pads squeezed, and turntable speed steady. As the mainsprings unwind, the tension reduces, and then the friction pads are allowed to expand, and in some instances....expand and contract depending on the warpage in the 78rpm disc (I know, sounds freaky).

This is a common problem on older Victor models that have leather friction pads. Simply replace the leather pads with two cut down pieces of treadle sewing machine leather belt (two 5/16 long pieces usually do the trick).

On Columbia motors, the friction pads are hard wool. Less of a chance that the wool has gone bad, but i have seen it happen!


ALSO: the friction disc might be bound up with old varnished oil on the governor shaft. If this is the case, the speed will be VERY inconsistant as the governor assembly won't be able to react to variations in torque. This will require removal of the governor assembly, and removal of the governor shaft from the disc.....cleaning off oil varnish with a Q-tip wetted with lacquer thinner.

-W

[De Soto Frank]

Thanks for the replies thus far...

I will inspect for worn gears / mashed teeth, bent parts, and sticky, varnished-up governors...

I believe one of the bevel-gears is fibre ? ( The right-angle power-transition is achieved via straight-cut bevel-gears, rather than helical/worm like later machines... straight-cut gears tend to run "noisy" in my experience...

Gives me an excuse to play with my dial-indicator...



The motor sounds a little "rocky" when running at-speed... I don't hear it over the music, but it's a little "scary" when running alone...

[Phono48]

I had exactly the same problem with an early HMV motor. The problem was solved by meticulously cleaning the centre shaft of the governors, and the inside of the collar that slides along the shaft. I don't know whether there was residue of old oil sticking to the shaft, or a tiny bit of steel wool from the clean up of the motor, but something wasn't allowing the smooth movement of the governors along the shaft. Whatever it was, everything now runs fine. Hope this helps.

Barry

[phonogfp]

I clearly don't understand the problem! The "beats" and the "bars" confused me...

George P.

[De Soto Frank]

I clearly don't understand the problem! The "beats" and the "bars" confused me...

George P.

http://www.youtube.com/watch?v=Zh4n1X4osJQ




George, I started-out trying to document the anomaly in terms of number of revolutions of "slowing-down" and "speeding-up", but I just couldn't seem to make that work...


When I put in terms of musical terminology, it seemed to go better for me in terms of explaining it... not so sure how it "reads"... LOL