Pfaff 545 tension problem when using reverse

[baileyuph]

It has been a long while since I read the technical manual on this machine so am wondering why the seam tension goes awry when pushing the reverse lever?  Had this problem before but like stated haven't had any problems recently and have gotten cold on trouble shooting.

It sews a very nice seam forward, but when the reverse lever is raised, the upper tension gets very loose.  This loose tension shows up on bottom side of seam and it is the needle thread that get way loose.  Just thought I would run this by you people, before I am forced to dig into the manual.  Lazy ?.........I guess. But I am busy. 

The machine goes in reverse, but the upper thread as it appears on the bottom has a lot of slack.

I did clean the thread paths of both the upper and the lower thread.  Like I said, it sews a straight seam very nicely. 

Just thought I would run this by you smart people.

Doyle

[65Buick]

I have this exact machine. I also had this exact problem and asked for advice from a man who runs a sewing machine store.

His words: Upholstery machines are notorious for goofy backstitches. He recommended that instead of actually reversing (like when locking a stitch in) raise the lever to 0, so that it sews in place. I have found this to work.

My machine almost never fails to jam in the reverse stitch, especially when starting a seam. My particular machine was used for many years by a shop that sewed canvas and then it was sold back to a different sewing machine shop. That shop had an expert tune up the machine, which I believe, because they tune for Patagonia.

Which leads me to my next piece of advice: The bracket that holds down the check spring was completely gummed up with bits of thread. Once I cleaned all that all and made sure the check spring bounced up and down, life was good. The upper thread needs a lot of tension to work properly.

[Tejas]

For similar threads, pun not intended, on another forum that might help, you could try the following in google:

tension problem in reverse site:leatherworker.net