SL-1500C tonearm shape defective?

Yes, the pipe is rotated clockwise. It may be possible to correct it.

If the table is new, the OP should contact the dealer.

 

The tonearm looks fine. I guess the headshell is just mounted at an angle?

 

+1

 

Locking collar set screws are shown to be a bottom of tonearm so BENT, either tonearm or PIVOT area, seems to be the condition and a good place to check for damage.

 

It’s a bit hard to see it from that angle because it’s S-shaped. The stylus doesn’t point straight back at the pivot. But yes, the back of the tonearm is higher than the front.

I was wondering if anyone might know what those two little screws on the bottom of the tonearm do, and whether tightening or loosening them would affect the angle of the locking collar and in turn, the headshell.

 

Those screws keep the locking collar in place.

 

So they can’t be used for adjustment.

 

They could be used to adjust azimuth, not VTA.

 

There might be enough play to make an adjustment at the shell, but the azimuth adjustment should be made at the pivot as this is where the problem originates. Because the pipe is rotated, instead of the bend in the pipe being perfectly lateral, it dips down from the pivot then back up towards the shell. This is clearly visible in your photos.

Take another photo, this time from far enough back to reveal the full extent of the arm. You will see the bend behind the shell is the lowest point, where in fact it should be the same height throughout.

 

How do you adjust azimuth at the pivot?

 

I'm not familiar with how that arm is assembled. That's why I suggested you contact the dealer. If it is still under warranty, it needs to be repaired or replaced. If that isn't possible, there may be images on the web that could provide a clue.

 

Azimuth is not the problem. I only mentioned it because someone asked about the locking collar screws, which could possibly be loosened to allow the locking collar to be rotated to adjust azimuth. The problem is likely a bent tonearm, very slightly bent.

 

Yes, but the bend is intentional...the rotation is not. The rotation can be rectified at the shell to correct azimuth, but then you wind up with the problem the OP has.

 

I’m still having back and forth with Technics support.

 

Just fyi, assuming the 1500 is similar to the 1200, there are two screws on the bottom of the arm tube in the front to hold the collar, and then two screws in the rear in the pivot assembly to secure the armtube, as shown below from bottom (and neither is intended to adjust azimuth) ... so it's possible a batch of armtubes was drilled and tapped a little off, which would rotate the arm ...

 

The bend I suspect in the tonearm is vertical. Bent down somewhere just slighly in the middle will produce a tail high headshell condition, which cannot be corrected without eating up all the VTA adjustment available. This is as the OP has described it since his first post; and, since, as I understand it, the TT is a demo model, it's easy t believe the tonearm might have been bent by a very aggressive prior user.

 

Yes; yet, it appears the issue here is not an arm rotated out of position but instead a tonearm which is bent downward in its middle slightly. That's how it looks to me and the OPs actions to level the headshell, which makes the tonearm pivot high and low at headshell tail supports my reasoning.

 

Below is a picture of the underside of the arm tube, with the threaded-hole pivot end closest to viewer. If you put a little spacer under the bend on the right to rotate the armtube slightly, that will make it bend down in the middle and make the headshell end point upwards when installed. I don't know if the holes and thread are done before of after the bending, but something off on one of the machines could easily cause this issue (at least from the way I read the description) and there could be many examples out there with the same issue ...

 

Yes, I think you nailed it.

 

It would take considerable force to bend the pipe, enough to damage the bearings and leave marks on the pipe. I can't imagine how such abuse would not be noticeable in other ways.

 

The screws may not be intended to adjust azimuth, but the tolerances may be large enough to permit the rotation. 1° would be enough to cause problems.

 

I totally agree.

 

Sure, but if you look more closely you'll see the screw heads mate to a flat surface on the casting, so I don't think you could rotate the armtube since it will return to the original position when the screws are tightened.

 

That's a good point, but now I'm wondering if the pipe itself is tapped, or if there's a tapped plug inside. The latter would be stronger, and opens the possibility for misalignment.

 

The pipe is tapped with metal screws ...