Idler Alignment Walk-Through

[stevenarrow]

Hello all,

I'm in the process of getting my PTP Lenco back up and running with a few new Audio Creative parts, but I’ve run into an issue with aligning the idler wheel to the motor. I’ve noticed a good deal of brushing noise from the wheel on the underside of the platter, and by eye, the alignment seems significantly off.

I’ve seen some helpful templates and plan to build one next week to double-check the alignment. However, I’m not sure what the actual adjustment process is. Does the idler arm grommet connection play a role here? Is there something I need to adjust in the mounting? Or do people actually bend the idler arm to correct alignment?

Any advice on realigning the wheel would be greatly appreciated, as I’m at a bit of a loss here.

Thanks in advance!

[rfgumby]

Ooh, yeah.  In my experience the wheel should be parallel to the bend in the arm.  It pointing in (towards the platter pivot) could very well make scrubbing noises.  I'd suggest carefully bending it back out.  I don't believe it's risky, but if it fails at least it's a very common part.

You'll also want to replace the grommet on the arm pivot end, if you haven't already.

[SteveM]

The wheel is aligned to the platter, not the motor.
In a perfect world* a line through the wheel axle would go to the center of the platter spindle.
The motor sits in a "best compromise" position.
Hopefully your PTP plates are positioned correctly.
As for the grommet search for posts written by macuser.

*Lencos are not perfect

[awkwardbydesign]

What you need is one of these.  I made mine, but I believe you can buy, or even borrow, one here.  Not only does it show the angle (90 degrees to the spindle is correct), but also at the correct height, as it is made to be at the same height as the underside of the platter.  Mine is set to 25mm for the PTP6.
And yes, you bend the idler arm to set it square; the arm should ideally be parallel to the top plate.

PS. I see Robertson screw heads!

[Andrew.R]

Where do you get one of those? 

[stevenarrow]

PS. I see Robertson screw heads!

Yup. I’m Canadian.

I just used whatever was on hand for this ‘temporary’ mock up. That was 6 years ago…

[awkwardbydesign]

Where do you get one of those?  

https://www.lencoheaven.net/forum/index.php?topic=3667.0
Oh, and I should have said align the wheel at 90 degrees to the surface of the drive spindle, not the axis.

[Andrew.R]

https://www.lencoheaven.net/forum/index.php?topic=3667.0
Oh, and I should have said align the wheel at 90 degrees to the surface of the drive spindle, not the axis.

I thankyou!

[SteveM]

https://www.lencoheaven.net/forum/index.php?topic=3667.0
Oh, and I should have said align the wheel at 90 degrees to the surface of the drive spindle, not the axis.

No, you should not have said that.

[stevenarrow]

Thanks for the input all -- I think I have everything I need to build a template and test actual alignment of the wheel to the spindle in reference to the underside of the platter.

Will post progress as it develops.

[awkwardbydesign]

No, you should not have said that.

The first bit or the second bit?

[SteveM]

The bit about the drive spindle.

[awkwardbydesign]

  Which part of my post do think is wrong? Axis or surface?  Please explain.

[stevenarrow]

I dont understand what the surface of the spindle is as a reference point. The axis is straightforward.

[awkwardbydesign]

Ah, OK.  The surface is not parallel with the axis, so setting the wheel relative to the axis will make it out of alignment, more at one end than at the other.  I set it at 90 degrees to the 33 rpm part of the spindle, as that is what I use 99.9% of the time.
 EDIT;
I have now remembered what I did (getting old, memory getting worse!).  I adjusted the angle of the spindle, by lowering one end of the motor to get the surface at the right angle.  This keeps the wheel/platter alignment correct.
It may or may not make an audible difference, but anyway, that's what I chose to do.