Thumping Sound...Your Opinions?

[ttman57]

A couple of years ago when I purchased my Pioneer PL-514, something I noticed when playing a record was this "thump" sound as the table rotated. You can only hear it through the speakers when the needle is on the record. Thump....thump....thump....thump.

I was wondering, if the turntable was not used for a while until I got it, could it be that the belt is causing this? Like perhaps a bad spot on the belt? I also noticed this morning that there seems to be a slight burnt rubber smell after playing. I am considering buying a new belt to see if this remedies anything.

Also, could it be that there is a bad bearing problem? I hope not. Opinions and thoughts on this are appreciated.

[paul401]

Hello,
belt would seem the obvious cause, take it off and look, might see/feel a nick/dent in it. Any physical artifact on the drive system will cause a noise through amp/speakers when the stylus is on the record.
Check the motor shaft for traces of old rubber/belt and clean off. Also check the spindle bearing isn't dry.

Paul

[Brick]

Check to be sure the shipping screws are out of it, as well. Bought a "nonfunctional" table one time that still had the screws in it.

[RedCloudFuneral]

Going to bump this thread, I'm having the same issue with a Dual 1209 idler drive table. Happens only when the stylus is on the record, loud and clear between tracks. The noise is rhythmic in nature like a metronome.

[Alec124c41]

Going to bump this thread, I'm having the same issue with a Dual 1209 idler drive table. Happens only when the stylus is on the record, loud and clear between tracks. The noise is rhythmic in nature like a metronome.

If the turntable is left sitting for a long time with the idler in the on position, the pressure from the drive spindle in one spot will leave a dent in the idler.
You may be able to dress the idler back to round, or you might need a new idler.

Cheers,
Alec

[hexen]

I was always under the impression that this happens when the player is not level. Is this not the case?

[dodgeone]

Hi, Newbie here.....
I have an old Onkyo turntable with linear tracking.
The tone arm is assisted across the record grooves with a small motor that couples to the tone arm mechanism via a small rubber belt. This belt can begin to slip over time. On my old Onkyo this caused the same symptoms you describe. As the belt slips the drive electronics keep telling the motor to 'Catch up' with the tone arm position relative to the record groove at that moment in time. Thus, instead of smooth tone arm tracking, you get a rhytmic pulse that is audible in the audio.
Hope this helps.
Steve H.

[ttman57]

Okay, I finally got around to pulling my TT out of the entertainment center.

I cleaned off the motor shaft, as there was a bit of residual rubber from the belt. Not much, just a tiny bit. I cleaned the same from around the platter. The belt itself seems not too bad. I can feel a slight, small spot on the belt when I run my fingers around it. Don't know if this is what is causing the thump, but I'll get a new belt, anyhow.

As far as a user mentioning the spindle bearing...help the ignorant here; where is it? How do I get to it? What will I be looking for?

As far as any lubricating in the PL-514 manual, the only thing they mention is putting two drops of oil in these small holes above the motor, where the shaft is. I will do that as that is simple.

As for this thing about the tonearm playing "catch up", that's way over my head. I hope that isn't the problem.

The only other problem will be the scent of rubber, like it is getting hot or something. No one here addressed that for me. Until I get a new belt, I'll try this one and see what happens.

Also, besides this spindle bearing, which I need help finding, is there any other areas that may need checking or lubricating?

Sorry for dragging this on, but I don't want my TT to get worse if things can be done to help improve it that are simple in nature. I tried to find a "service manual" here for this TT, but could not find one, just a users manual. I thought a service manual would have been a big help.

In the meantime, I hooked up a Kenwood KD-40R TT. Not near as nice, but adequate.

As always, everyone's help here is greatly appreciated.

[Alec124c41]

The spindle bearing is what the platter rotates on. The platter, with no belt, should spinn easily and silently, for quite some time, when given a push. I expect yours might not spin long.
Remove the platter, set the belt aside, and examine the spindle assembly. You want to get the spindle to lift out of the bearing well so you can clean it with Q-Tips and isopropyl alcohol. Then add 10 drops of good oil (not the regular 3-in-1). Replace the spindle, and clean up any oil that gets out.
Do not get any oil on the belt, or the surfaces it touches.

Cheers,
Alec

[ttman57]

I took a look at the PL-516 service manual, since the PL-514 seems impossible to find. I think I can get to the bearing without much difficulty. I was concerned before, so I did not tinker with it.

I'm bumping this thread now as I am buying a new belt today and am wondering, what do any of you use to lube the shaft bearing? I keep seeing this synthetic lube on eBay. Any opinions on that or other lubes?

Thanks ahead of time.

[Bob in STL]

The spindle bearing is what the platter rotates on. The platter, with no belt, should spinn easily and silently, for quite some time, when given a push. I expect yours might not spin long.
Remove the platter, set the belt aside, and examine the spindle assembly. You want to get the spindle to lift out of the bearing well so you can clean it with Q-Tips and isopropyl alcohol. Then add 10 drops of good oil (not the regular 3-in-1). Replace the spindle, and clean up any oil that gets out.
Do not get any oil on the belt, or the surfaces it touches.

Cheers,
Alec

Hello Alex,


I just refurbed a PL-514. It plays and sounds very good.

As part of the refurb I oiled the motor with a few drops of sewing machine oil. I have a new belt on order. I noticed that my platter does not turn freely with the belt off as you desribed. I am sure it is the original lube in there so I took it apart and checked, even though it works fine.

Looking at the grease in the bearing well, it is black and sticky and in need of replacement. I cleaned the entire assembly with isoproply and now I am wondering what to put in it?

Silcone grease? Oil? Any name brand product to recommend?

thanks, Bob

[Bob in STL]

I took a look at the PL-516 service manual, since the PL-514 seems impossible to find. I think I can get to the bearing without much difficulty. I was concerned before, so I did not tinker with it.

I'm bumping this thread now as I am buying a new belt today and am wondering, what do any of you use to lube the shaft bearing? I keep seeing this synthetic lube on eBay. Any opinions on that or other lubes?

Thanks ahead of time.

I just took one apart and I can help you. PM me if you need help.

Also, be careful, there is a ballbearing at the bottom of the bearing well.

I am looking for the right lube too.

Bob

[cafe latte]

The best oil to use on turntable spindle bearings is spindle oil or compressor oil which you can buy cheaply from motor parts stores, or if you live in the USA (cant buy it here in Australia) 3 in 1 blue is also ideal, but NOT the normal 3 in 1 red! I use compressor oil iso 46, but heavier will also be fine too. Normal motor oil is no good as the additives can damamge spindle bearings and sewing machine oil is only 5 or 10 weight so is too thin.
Hope this helps
Regards
CL

[Dimal]

sewing machine oil is only 5 or 10 weight so is too thin.

Why do you say this CL?

Straight Turbine Oil is by far and away the best oil to use if you can locate some in a small quantity, and it is quite low viscosity. Thinner oil rather than anything 'too thick' is actually better for these types of bearings. Ensures that the bearing interfaces are always 'wet', thereby preventing wear... Thicker oils can tend to 'shear' in bearings with such fine tolerances.

Mal.