Adjust speed adjustment knob on a Diamond Disc machine

[Edisonh19]

Hi folks. A quick question about the speed regulator knob on an Edison Diamond Disc machine. When the knob on my machine is turned the whole way to the stop pin, it *just* plays at 80 rpm. Is there a way to adjust this knob so that it gives a wider variety of speed selections? Some discs seem to sound better played a smidge faster.
Thanks!
Ed.

[52089]

Yes, you can move the governor very slightly. Search the board for amore detailed answer, and remember to make sure the springs are fully unwound before starting.

[estott]

That stop pin was not intended to set the speed limit, someone has fiddled with your machine

[Edisonh19]

In looking at the machine and the mechanism that moves the felt pads back and forth near the governor, I can see where it would be adjustable. Does anyone know which screws to use for adjustment? I have not been able to locate instructions for adjusting that mechanism. I am familiar with how the speed adjuster knob should function, I have another DD machine, and it reaches 80 rpms when the knob is still about ¼ turn from the stop pin.

[fran604g]

Ed, I'm not certain how familiar you are with the mechanism, so here is a link to the manual for maintenance, repair and lubrication for the Diamond Disc mechanism.

http://forum.talkingmachine.info/viewto ... ?f=2&t=476

You may need to simply oil the governor friction (speed regulating) pads. See the section titled "The Governor". I would try this first, then proceed with other alternatives, if necessary.

This is the exact sentence from the manual that may be the solution to your issue:

"THE GOVERNOR

(1) If the governor is not well cared for, it may give a whirring noise and a change of speed will be noticed with a consequent drop of pitch of music. The lubrication of the end bearings of the governor shaft is taken care of by oil tubes leading from oil cups (3), Figure (5). To prevent accumulation of grit upon the friction pads (1), Figure (5), clean occasionally with the use of a few drops of gasoline. Allow the motor to run a moment and then apply Diamond Oil to the pads."


Fran

[fran604g]

I finally found time to go out into the shop and snap a picture of the underside of one of my Type B mechanisms (c 250 #54408).

I also noticed that the earliest mechanism I have (C 250 #6947) does not have this provision. Apparently, the "pointer" under the speed control knob was changed via 2 set screws, and rotated on the shaft to allow more, or less, rotation of the knob before coming in contact with the limit pin.

The image below shows the adjustment screw (an "eccentric" screw) found on the governor friction pad control linkage assembly.

I'm not sure how you can access the screw from the underneath while the mechanism is in the cabinet, so likely you'll need to remove the mechanism to make the adjustment -- unless you are more of a contortionist than I am.

Also, I'm sure you'll need to make very small changes while frequently checking the speed.

TURNING THE SCREW CLOCKWISE WILL ALLOW FASTER TURNTABLE RPM

TURNING THE SCREW COUNTERCLOCKWISE SLOWS TURNTABLE RPM

Good luck,
Fran

[Edisonh19]

Thank you Fran, that was exactly what I needed! Fixed the problem in 2 minutes flat. I was able to reach the screw through the grille opening. Just have to strategically place a flashlight and watch the movement of the felt pads at the governor as you move the screw. Plenty of speed range! The motor is buzzing right along at 80rpms now.
Thank you!
Ed.

[fran604g]

My pleasure, Ed.

I'm happy you could reach the screw easily, I have serious problems bending and reaching, so it would have been a near impossibility for me.

Glad it worked out!

Fran

[52089]

That stop pin was not intended to set the speed limit, someone has fiddled with your machine

I would have to disagree. The earlier motors with decals around the speed control make it clear that the knob should be turned all the way over to the stop pin, and that that is the correct setting for 80 RPM.

[fran604g]

I would have to disagree. The earlier motors with decals around the speed control make it clear that the knob should be turned all the way over to the stop pin, and that that is the correct setting for 80 RPM.

I agree completely. The pointer should be calibrated to contact the pin when the turntable rotates exactly at 80 RPM.

Quite a lot of time, money, and energy was expended by the Edison engineering department to design and manufacture an incredibly accurate and reliable motor.

It's consistent with their philosophy to have produced a product that was on par with a scientific instrument, and the user interface of the speed control would certainly have been meant to be precise.

Best,
Fran