sm74 4th inker not adjusting to plate

hi all,...wonder if you can help. ive been trying to figure out why my 4th inker will not go to plate. firstly ive set the internal to oscilator and the roller ( yellow ) is 65.5 mm. it fires down on operators side but drive side has nothing. almost looks as if it is missing pneumatic pressure but from what i can see from the parts book it is driven soley by the adjustment of the 3rd (red ) This is happening on all units and i know its nothing ive done as i have set these up too many times.....didnt know whether there was some kind of modification that was done and something i need to be looking for. Any help Or advice would be much appreciated

 

my first suggestion would be to pull the roller out of the press and measure its diameter to make sure its not undersized. There are limitations to the adjustment amount. If roller measures within spec id be looking at the cups and the rod on the cups to be sure they are coming down all the way and not causing a misalignment. You can measure against a known "good" unit.