I recently purchased a used Happy HCG-X1204B-45TTC 4 head. Its old but has been in storage for about 10 years and looks new and runs well, also just been serviced, not by a Happy engineer but thats another story.
The problem is I cannot get the tension balance right, with not enough bobbin showing on my tension tests. I have attached a couple of pics.
I use the Tajima gauge for the top tension and the Towa gauge for the bobbin. I have had to reduce the bobbin tension to 18 on the Towa and over 150 on the Tajima gauge and still not happy with the amount of bobbin.
I am reluctant to reduce the bobbin tension anymore and dont think I could increase the top tension as I feel I am on the absolute limits.
Btw, I am using Madeira Classic #40 whose recommended tensions are 18 - 22 for the bobbin and 100 - 120 for the top.
I have a Tajima single head with the correct tensions set using the same gauges with no issues. This is my first multihead so maybe things are different?
Is this a tension issue or a symptom of a more serious problem?
I would appreciate any advice.