Erratic Turntable Speed - I'm Stumped

[OrthoSean]

Bob's suggestion is exactly what I was going to say. For some reason, Columbia motors and some (OK, two I've worked on) Edison DD motors seem to be prone to this. Smooth out the two pads, make sure they're both equally as even as they can be, then soak them with oil. I've had several Columbias do this over the years and this was the issue 90% of the time.

Sean

[Henry]

What Sean said. I just noticed that this machine uses two pads on the governor disc, unlike VTMCo who used only one IIRC (e.g., as on my XI-G). Thus any uneveness or inequality in the contact zone or pressure could result in speed variation. Of course, any eccentricity in the rotating parts, i.e. shaft, disc, could also produce the symptom.

[CDBPDX]

I took the motor apart again and removed the governor. It is one with an eccentric seat on one end to adjust it's position relative to the gear on the spindle. It was a wee bit tight so I loosened it a little, made a noticeable difference in resistance to spinning. Also cleaned and lubed the governor seats and reinstalled with only the tiniest bit of play. I filed a tiny ridge off one of the brake pads, then ended up filing both pads to exact size, then oiled the pads. Checked the ease of sliding for the springs and weights and found that to be good. Oiled it anyway. Put it all back together with high hopes but it was immediately apparent that the problem had not been resolved. It was as if I had done nothing.

It is nearly impossible to set the speed with a strobe. It seems to be constantly changing ranging from approximately 90 rpm to 70 rpm no matter where I set the adjust lever. There are periods when it remains constant but that only last at most about 20 seconds then its off to the races again.

Back to checking the gears, I guess...

Cliff

[Phono48]

I've had exactly the same problem recently with an HMV motor. After many frustrating hours, I found that the spindle that goes through the centre of the governor assembly was sticky with old grease, and wasn't allowing the governors to expand smoothly. I removed the assembly from the spindle, cleaned both the spindle and the hole it passes through on the governor assembly, then polished the shaft before reassembling, and applying a drop of sewing machine oil to the shaft. Problem cured!

Barry

[Henry]

I've had exactly the same problem recently with an HMV motor. After many frustrating hours, I found that the spindle that goes through the centre of the governor assembly was sticky with old grease, and wasn't allowing the governors to expand smoothly. I removed the assembly from the spindle, cleaned both the spindle and the hole it passes through on the governor assembly, then polished the shaft before reassembling, and applying a drop of sewing machine oil to the shaft. Problem cured!

Barry

See also my post in re: clean mechanism. To quote Pooh-Bah (or was it Ko-Ko?), "Glad to have my opinion backed by so competent an authority."

[rizbone]

If the governor springs have oval holes in the end perhaps one of them is loose and is changing lengths? Just a guess since it sounds like you have tried everything else.

[Henry]

If the governor springs have oval holes in the end perhaps one of them is loose and is changing lengths? Just a guess since it sounds like you have tried everything else.

For that matter, the springs themselves may be weakened from age and use. Is replacement in order?

[CDBPDX]

So, I removed the governor and disassembled it, cleaned everything, reassembled, and reinstalled.

Cranked up the motor and now it runs smooth as silk at a constant speed. Guess it was gunkier than I first thought.

Thanks for the good advice!!

Cliff

[barnettrp21122]

Great! Good to know the problem's solved! Have a nice weekend.
Bob

[RAK402]

Thank you for posting the resolution to the problem. That will help others in the future!
(me included!).