ShirlinAZ,
On a situation like that the only thing I've found to work is to remove the top tension, disassemble it and thoroughly clean it. Dry it, reassemble it and then adjust it.
Might as well do the bottom end at the same time.
The TFSR manual {
http://www.tfsr.org/publications/tec...machine_manual } contains all the information you'll need to do the job.
Joe