clean and grease the mast channels esp if they are new and dry (light coat dont gob it, too much grease will make the rollers slide not roll)
look for bad rollers, ball bearings can fall and stop the mast up by getting stuck between another roller and the channel
the load may be adding friction to the assy
ive had to grease many a mast cause they wouldnt collapse in sequence
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.