HP 1055CMHP - Manual (Page 17)

Troubleshooting
1-5 HP DesignJets 1050C and 1055CM Printers Service Manual
The Printer does not Power ON
1 Check that the power cord is connected correctly to the Printer and
to the Power Socket.
2 Check that the Firmware DIMM is installed correctly in the correct
slot (the first slot from the right) at the back of the Printer.
3 Check that the Power Switch on the BACK of the Printer is in the
ON position.
4 Check that the Front-Panel Cable is correctly connected to the
Electronics Module. Also make sure that the Front-Panel cable is
not damaged.
ALL the Front-Panel LEDs are Lit but Nothing Else
Happens
The Firmware DIMM is NOT correctly installed.
1 Power OFF the Printer from the back and disconnect the power
cord. Reseat the Firmware DIMM (the first slot from the right)
making sure that it is installed correctly.
One of the Print Quality LEDs on the Front Panel is
Lit (and nothing else) and the "SELF TEST..."
Message Remains on the Front Panel
One of the DRAM DIMMs is NOT correctly installed or Faulty.
1 Power OFF the Printer from the back and disconnect the power
cord. Reseat both Firmware DIMMs (the first two slots from the
left) making sure that they are installed correctly. If reseating the
DRAM DIMMs does not solve the problem, replace them instead.