Yamaha PX-3 Tone Arm Issue

[RCHeliz]

Hello everyone,


I'm having a problem with a like new Yamaha PX-3 Turntable. I recently took it out of the box and set it up.
Added a new Denon DL-110 cartidge and left it overnight to break in.
In the morning this is what I found:

It seemed to be okay-ish up to about half the record tracks then it starts doing this.
Can someone help me find the problem? Worked ok initially when playing a few records but then it started doing this. Controls work fine LEFT/RIGHT from the buttons on both speeds slow or fast.
Also when pressing/tilting right on the arm pipe it follows to the right ok, but when pressing left it seems slow and intermittent.

Any suggestions would be appreciated.
Thank you in advance!

 

[Nashou66]

Welcome to AK !!!!


Could be the rod the arm travels on needs to be cleaned of the old grease and re lubricated and or the belt for the tone arm needs replacing. Just had to do the same for my Technics SL-M3.

Nashou

 

[audiocrzy]

Welcome to AK !!!!


Could be the rod the arm travels on needs to be cleaned of the old grease and re lubricated and or the belt for the tone arm needs replacing. Just had to do the same for my Technics SL-M3.

Nashou

I don’t think the rod is greased or oiled at all. It still could be the rod but it just might need a good cleaning.

 

[loudnoises]

I don’t think the rod is greased or oiled at all. It still could be the rod but it just might need a good cleaning.

If the tonearm belt hasn't been replaced, do it. It's aged and not working as well as it should.

 

[MRL_Audio]

Probably the belt is worn and needs to be cleaned. Do not lubricate the rod. It just needs to be cleaned of dust and debris. More than likely you have a belt issue.

 

[audiocrzy]

Probably the belt is worn and needs to be cleaned. Do not lubricate the rod. It just needs to be cleaned of dust and debris. More than likely you have a belt issue.

I agree with this. Don’t replace the belt unless absolutely necessary. I have the PX2 and 3 both of them having had the tone arm stalling issues that were addressed without replacing the belts. I didn’t have to do it but I did see a thread explaining how to turn the belt over to use the other side as a solution to it slipping. The belt springs can also be shortened. That’s what I did on mine and it cured the slipping problem.

 

[Fishead]

I am reasonably sure the large, flat tonearm belt is unobtainable unless you source it from another table for parts. You can, however, turn it over and there are instructions here and elsewhere for how to do that. The small o-rings are available and these may be what is needed. https://www.lpgear.com/product/PX03.html

Do a search here and you will come up with some solutions that others have arrived at. Good luck, it's a fine table and I'm still running mine after nearly 40 years! They are not, however, without their gremlins.....

 

[RCHeliz]

The wide belt is in top condition. Also the other 3 belts are good, no crumbling. I did spray all belts with CRC Belt Conditioner.
They are drying, I also lubed the roller hinges and all moving parts with turbine oil. The rail rod does not need to be lubed. I will do some NuFinish on it as it will leave it in a very smooth state. The rollers are moving smooth and all moving parts turn freely when I give them a spin and continue to spin. If one thing I'm good at is fine mechanics. Now the electronic parts I'm worried about. I hope its not something inside the tone arm or main board not giving the motor enough power making it stall at slow speed. Will reassemble and test again.

What about caps, should I recap it?

 

[pfcs49]

Those flat belts look good, they have no "set" in them from 35 years being parked on the left and right rollers.
A rarer mechanical problem might be that the 2nd stage reduction shaft, that's serrated on it's end and drives a flat rubber "wheel" on the end of the driving drum for the flat belt, may be slipping.
I think if you remove the cover behind the tonearm assy you may be able to observe everything and see where the problem is, if it's a mechanical one. Understand the this exposes the tonearm position sensors to ambient light which sometimes has unintended consequences, causing the tonearm to misbehave.

This thread has relevant info and a link about the rubber whee/drumhttps://www.audiokarma.org/forums/index.php?threads/px-2-tonearm-drives-whats-really-original.344820/

and here, post #9, shows how to determine if your flat belt is stretched. If it isn't, I wouldn't advise tightening the springs.https://www.audiokarma.org/forums/index.php?threads/still-no-belts-for-yamaha-px-3.467030/

PS: I'd wipe down the wide belt before installing it. In fact, my habit is to wipe it down shortly after treatment.

 

[Dr. Ear]

It is not an electronic issue. The tension of the transport belt might be not sufficient. I have done 4 PX which showed identical symptoms. Increase the tension of the transport belt by shortening of the two springs (5-7mm).

 

[pfcs49]

It seemed to be okay-ish up to about half the record tracks then it starts doing this.
Can someone help me find the problem? Worked ok initially when playing a few records but then it started doing this. Controls work fine LEFT/RIGHT from the buttons on both speeds slow or fast.
Also when pressing/tilting right on the arm pipe it follows to the right ok, but when pressing left it seems slow and intermittent.

You could try doing the above (with "play" engaged, lifting the arm off the record and swinging it left or right to see if the servo responds and nils the change in tangency) with the deck inclined a little towards the left so if the drives are complying you'll pretty much eliminate electrical problems. Likewise, you can see how much an incline the arm will climb leftward and rightward using the <L & >R buttons.

 

[pfcs49]

It is not an electronic issue. The tension of the transport belt might be not sufficient. I have done 4 PX which showed identical symptoms. Increase the tension of the transport belt by shortening of the two springs (5-7mm).

IMO, if you can restore performance and the belts aren't stretched, there's no goo reason to do this. I've redone five decks and only one had stretched belts, and not so much either.

 

[Dr. Ear]

After 30 years the belt is stretched, at least a bit.

 

[Dr. Ear]

... and spring tension is not like new.

 

[RCHeliz]

Thank you for all the suggestions above, been through some of those before I posted here.
The carriage moves smooth as silk. Belts have dried and look great even though a bit sticky...
Will check belt tension after attaching springs.

Here is what I have done so far... Even checked the optical sensor in the arm which was a tiny bit crooked horizontally...(what an ancient photo sensor bleah!)

 

[clinic-audio]

Hello RCHeliz

I know perfectly PX3, PX2 and PX1
I am working right now on a PX1 who will be ready next month (long , long , work)
Regarding your trouble : it is the same on all YAMAHA PX3 and PX2
The problem is coming from here :



the problem is that the flat belts slip on the pulley and the motor can't compense enough to keep the tone arm strait

The only way to repair it is to replace the drum by one upgraded one like this



this new drum will never slip and your tone arm will go back to normal function

 

[pfcs49]

I don't agree that the only way to repair it would be to install your up-rated drum and wheel-I've not needed that kind of remedy yet, but I do agree it would probably resolve any problems with the drum-tire slipping on the second stage pinion OR the final drive drum slipping in the belt! Very nice upgrade!

I advise you to delete your seeming offer to sell your drums. That is exactly how Dr Bitz got banned here!

 

[pfcs49]

After 30 years the belt is stretched, at least a bit.

... and spring tension is not like new.

Post #9, Still No Belts...
"I've had a pair of new OE flat belts for as long as I've been involved with these tables. Here is the information:
that's the boyscouts marching song (Tom Leher 1953)
Although never a scout, I managed to secure a complete set of belts, knowing they were a likely end point issue as well as 3 opto couplers. (No they're not for sale)
The small belts are PN CB603040
they are "square", 1.59mm/.062"
They form a circle that is 1.088"/26.62mm (these measurement were taken accurately) Calculate length from circumference of circle if necc. It was removed from a hermetically sealed package. (if it biodegrades, you owe me one! I don't think so. I've had 4 PX 2/3s and never needed any of these parts)
On another related note Prof Bizzt says you cannot shorten the main belt springs. This is nonsense. Measure the belts from the holes in the middle (not the spring eylets because you need to measure them to 1/32") The center of the middle holes is 10 1/4", end to end. Add the 2 lengths and subtract this from 21 1/2". The difference is the amount you'll need to tighten the springs to restore as new geometry"

Four out of five have been identical to new; the only one I shortened the springs on was about 3/32 shorter.
Regarding springs losing tension: only to the extent they are (very) rusty. Any tempered spring (which these surely are as you see who rebounding the tail!) will not loose rate in a low stress and very slight activity application like this. Imagine the stress a coil spring in an automobile tolerates. Some will fatigue and break, but finding ones that sag is very rare! (45 years foreign car repair shop owner/race car fabrication)

 

[RCHeliz]

[

Hello RCHeliz

I know perfectly PX3, PX2 and PX1
I am working right now on a PX1 who will be ready next month (long , long , work)
Regarding your trouble : it is the same on all YAMAHA PX3 and PX2
The problem is coming from here :

View attachment 1775209

the problem is that the flat belts slip on the pulley and the motor can't compense enough to keep the tone arm strait

The only way to repair it is to replace the drum by one upgraded one like this

View attachment 1775214

this new drum will never slip and your tone arm will go back to normal function


View attachment 1775217

Wow! very nice, I'd love one of those.

 

[MRL_Audio]

Dr. Bitz. Now that guy has some stuff. Miss having him here.