Tech Help — Designjet 1050C 1055CM Technical Help

"I have a 1055cm plus on power up it goes to audible alarm no display on led panel any ideas??? Thanks Marty" The PCI bus on the main logic board is not relaying boot information from the ROM.  The ROM may be missing, the memory may be missing, the JetDirect card may be holding the bus down, or the HDD may be holding it down.  If the ROM and memory are present, remove the HDD and Jetdirect from the machine.  If the problem persists, replace the logic board. 

Any time the Designjet 1050C trailing cables are disconnected and reconnected because of a carriage replacement, belt replacement, trailing cable replacement or main logic PCB replacement, the resistance check MUST be made or risk blowing F7 or the main logic board itself. AFTER the trailing cables are attached, you need to read at least 100 ohms across the test points (more typically closer to 1000 ohms). The resistance will be moving and that is normal.  Zero ohms means a short and the trailing cables will need to be reseated.  HP put the ground and +5VDC .030” apart on the connector and...