Ribber carriage jamming?

Hi Sue,
Check your sponge bar/needle retaining bar in the main needle bed. When the sponge wears out there is not enough pressure on the needles and problems such as you are experiencing occur. The sponge should be at least a quarter of an inch above the metal bar for the whole length of the bar.
If it is worn replacing it should rectify the problem.
Regards,

Sue
May 2011