Music Hall MMf5 motor noise

[calman46]

I can hear the motor running on my MH turntable and there is scorching on the motor shaft. I am the original owner and didn't play it to death ,I have other TT's. The motor is still playing at the right speed . Does the motor shaft scorching indicate that the oil impregnated bushing has dry out ? Is this motor repairable ? I found Bluz Bros website and they drop in replacement motors, any suggestions?, thanks

 

[George S.]

The heat is caused by friction, so yes, it's a lubrication issue.
I'd take the motor out, take it apart, clean all the old lubricant and dust out, and re-lube it. Keep the original motor rather than replace it.
Electric motors do need periodic maintenance.
Here's a photo of the last unit I disassembled, cleaned, and lubed. A Robo Fan.

 

[calman46]

I was able to take the motor apart . I was thinking just redistributing the original lube paste ,its not dry up and there's plenty of it, clean too. The bushings appear to be brass, not bronze anyway. All I have is super lube and light weight turbine oil which will probably run out. I can polish the shaft.

 

[George S.]

That grease looks similar to Lubriplate 105. I wouldn't reuse the old. New is readily available, perhaps down at the local auto parts store.
Also check for drag from the platter causing motor heating.
Many of us use Mobil 1 or any motor oil on our turntables. I fill my oil squirt cans with whatever is left after doing oil changes on the cars.
My AR XB still has the original motor and bearings since I bought it new in about 1974. It's seen nothing more than automotive engine oil.

 

[WOPL Sniffer]

I don't see any "scorching". Even if it was scorched, just playing it wouldn't cause that to the thick steel shaft.

 

[WOPL Sniffer]

Try some fresh grease, WHY would you use the OLD SHIT??????

 

[calman46]

I didn't use the old grease it looked ok but had a waxy stickie feel to it . I went with Super Lube in motor and some capstan lube I have for a Revox B215 for the main bearing. The manual suggested Mobil 1 or any synthetic with Teflon for the mail bearing, I think capstan lube fits the bill. The TT is running quiet now, time will tell. Thanks for all the replies. There wasn't any scorching maybe just old cooked in lube . The shaft cleaned up pretty good ,there is what might be and oil retaining line etched in it.

 

[WOPL Sniffer]

Amazing

 

[calman46]

The super lube didn't last the noise is back . The TT ran quite with no record when testing 3 for four times this week. After playing one LP the noise is back and the noise is there with or without a record on the platter or the belt connected .The motor is hot but I can touch it. When the motor cools downs its quite again. Besides the two motor bushings could something else in motor be causing this noise? I thought maybe a heavier lube but I'm not sure now .I'll look for Lubriplate 105 . In the mean time I have some Exxon Ronnex MP.

 

[George S.]

Perhaps the issue is platter bearing drag overheating the motor. I have no idea how that table is constructed, but my AR-XB uses a plain babbit bearing to support the shaft sides with a single ball that the platter shaft rotates on, in the bottom of the well. Motor oil is the lube.
If the ball was missing, the platter would still spin, for a while, until the motor failed.

 

[calman46]

The bearing is oiled and uses a white plastic-looking disc at the bottom to support the spindle. It is the original belt maybe that is dragging . The speed was never an issue so I haven't replaced. I'm going to run the motor with no belt .

 

[calman46]

when motor starts getting warm (no belt connected) the noise starts also. The hotter the motor gets the louder the noise.

 

[AngrySailor]

Try it again with light oil. That super lube is silicone based no? ProbBly need to clean that also.

 

[calman46]

I think the shaft (pulley side) has flat spots on it . With the motor in half's if I back out the shaft it spins smoothly all the way in it fells like step audio pot.

 

[George S.]

My AR also uses a Delrin plastic disk at the bottom. The ball sits on the disk. Make sure your not missing a ball.
If your motor shaft is worn, then there you go. But realize the magnets and windings as they interact can also make it feel like a "stepped attenuator".

 

[AngrySailor]

I think the shaft (pulley side) has flat spots on it . With the motor in half's if I back out the shaft it spins smoothly all the way in it fells like step audio pot.

Pics pics pics. Sounds like a thrust washer worn or missing in the motor.

 

[AngrySailor]

My AR also uses a Delrin plastic disk at the bottom. The ball sits on the disk. Make sure your not missing a ball.
If your motor shaft is worn, then there you go. But realize the magnets and windings as they interact can also make it feel like a "stepped attenuator".

Probably shaded pole motor, do any TT’s use permanent magnet?

 

[calman46]

Looking at the bearing with the big eyes it its white ball . I agree I think the stepped feel is normal . There were some marks on the shaft that came with 1000/3000 grid spinning in my drill press. The motor bushing must be bad. I will mostly just buy a new motor and belt . I give one more try see if it gets noisy.

 

[calman46]

New Music Hall motor and belt ordered about $85. Thanks for all the help and suggestions.