TASKalfa 2551ci with additional pf791 tray 3 error and jam 0503

[taskalfa]

Hi, has anyone seen this error on a pf791 in particular tray 3 , when customer goes to print to it the tray over lifts the inner tray which results in the metal lift plate stuck in vertical position and copier displays tray error and usually paper jam 0503. Have done firmware , replaced pick up assy and also tray assy. When on site I cannot get it to fault , I have a feeling it’s only happening when it goes to sleep mode. All other trays are fine. I’m thinking of ordering the main pcb on the optional paper feeder and also the engine pcb. Any help appreciated

[bsm2]

reseat the connectors on the board