Zeta tonearm strip down and bearing change.

[karma67]

So ive been busy over the last week,there has always been a slight bearing rattle since i bought the zeta in the lateral top bearing.

you can here it in this video.



so what to do??
After further adjustment to the top bearing i became clear that it was either to loose or too tight,there was no in between sweet spot.
After a call to a fellow Zeta owner,Roger at TPA it seemed the best course of action was to strip the arm completely and check all the bearings.

As there was no manual it was in at the deep end time!
Each bearing has its own cover disc,to access the bearings each one has to be removed,i made a tool up at work to do this.



Top lateral bearing cup cover disc.




With the bearing cover discs removed we can see 1 of the 4 bearing cups which hold the bearings in place.

Here's a photo of the top lateral bearing cup,the cover disc has been removed.



To remove the arm tube the 2 vertical bearings have to be removed first,they are held in place with grubs screws so i first removed them.
Once the bearing cups are unscrewed using my special tool you can withdraw the arm tube out from the back,whoops the finger lift wont go through the square arm tube block???
Apply some heat,i used hot air pant stripper and let physics to the rest,once there's enough heat the finger lift just pulls out,bingo! you can now remove the arm tube!

Now that the arm tubes out of the way you have to remove the bearing cones before the arm tube block can be removed.These are a push fit and again held in place with grub screws,some heat here gets them out .

Here's the underside of the arm tube block showing the bottom lateral bearing cone.



With both top and bottom cones removed the arm tube block comes away leaving the main c shaped block/arm pillar.

So here's all the parts.



Someones been here before!
The tonearm uses 3, 2.5mm ball bearings to each bearing cup,except my bottom lateral bearing has 4 much smaller bearings which dont even fully cover the diameter of the cup they run in??
Thats not right,i think ive found my problem!!

In this pic you can just see the smaller bearings to the right of the top bearing cup.



Feeling rather happy that id found the problem i ordered some new Silicon Nitride bearings,my thanks to angus for the advice

After work yesterday i started the rebuild.
All parts well cleaned with alcohol,basically its the strip down in reverse.
The bearing cones are put back in the arm tube block,then the bottom lateral bearings go in,then the top ones,a good tip here is to use Vaseline to hold the bearings in their cups,the cups have a small hole so once the arm is fully assembled the Vaseline can be cleaned away using wd40 squirted through the hole.



Lateral bearings ready for action!


Now comes the tricky bit,getting everything centered correctly,i used feeler gauges here,and got the arm tube in the right ball park,the final truing up i did when the arm was completely back together.



Here the arm tube is back in place and new tonearm wire inserted,



Anyone still following??

Right next i had to put the arm tube assembly back into the c shaped arm pillar,again final alignment is done when complete.

With everything back in place i set about getting everything totally true,careful loosening of one arm tube bearing and tightening of the other moves the arm tube left or right depending on where you need to be.Be very careful here as if you loosen 1 too much the cone slips out and you have to take the whole thing apart and re sit the bearings again,ask me how i know!!!

With everything all nicely squared up i had a lovely view from behind,ooh matron!





Nows the time to give all the bearings a good soaking in wd40 to remove the vaseline,i did this periodically about 5 times,wiping with kitchen roll.
With that done i called it a day.

First job today was to check how everything was,movement of the arm in all directions was good so i went on to re solder the tonearm wires.




And that's it folks,job done!
What effect has it had? well to start with the movement with the arm at balance is way better than before in all directions,the arm glides smoothly with no hint of sticking.
The head stock lines up with the alignment protractor grid lines at 90 degrees,before it didn't, and lastly here's a vid showing the greatly improved vertical free play.