TM9-2320-361-10 2-31. OPERATION OF PIPELINE CONSTRUCTION MAINTENANCE TRUCKS (Contd) NOTE Height of A-frame can be adjusted by making boom chains longer or shorter. Position A-frame at higher angle for heavier loads. (13) Take up slack in cable (16), and slowly operate winch (refer to b. of this para.) until A-frame (20) reaches operating position. If necessary, manually push A-frame (20) over center, until in operating position. (14) Fasten a second chain (22) to safety chains (21) and bumperettes (23) to avoid backlash. (15) Let cable (16) go slack, unhook U-bolt (18) and lower until flush with truck bed. (16) Remove hook end of cable (16) from pintle hook (17). 2-153