You should not be having any issues with newQuiltmaker if the upgrade was done correctly. I use the red dot for regular sewing and the yellow dot for all embroidery. That is exactly what I used for my 12,000 as well.
My tensions are set exactly as they were set at the factory and not been touched. I have owned the 7700 the 11,000 the 300E the 12,000 the 7700QCP and the 15,000 Quiltmaker and never have I ever touched the tensions. I think you might consider a trip to the dealer if you are concerned.
From: jan shaw <janrshaw@...>
To: onlinesewing-janome <email@example.com>
Sent: Wed, Mar 14, 2018 5:59 pm
Subject: Re: [onlinesewing-janome] Tension
I have the MC15000 upgraded to Quiltmaker. While using the yellow dot bobbin case and straight stitch plate for embroidery if I use a pre-wound bobbin of 80 weight and a 40 weight rayon on the top, I have the same issue as the original poster; no bobbin thread showing on the back, even if the embroidery tension is set to 10 (or all the way to the right). Or if I tighten the screw on the bobbin case 1/4 to 1/2 turn, this does not make any bobbin thread showing on the back of the embroidery.
If I use a 60 weight bobbin thread, pre-wound or wound on the machine I can see "some" bobbin thread on the back when using 40 weight thread on the top.
If I use the red dot bobbin case and 40 weight thread in the bobbin and 40 weight on top when looking at the back of the embroidery I have the classic 1/3rd top thread 1/3 bobbin thread 1/3 top thread showing.
Question: Is this the software "glitch" referenced above with the 12000, or does the Janome not "play well" with such a difference in bobbin weight to top thread weight? Or does Janome not use the 1/3,1/3,1/3 rule for the back of a piece of embroidery?
The machine has been serviced twice since I noticed this.