Troubleshooting - NEC VT440 Service Manual

TROUBLESHOOTING

Operational checks
By making checks on operation under normal working conditions, a certain degree of fault diagnosis can be
carried out. Prior to removing the top cover, make the following checks:
• Is the POWER indicator lit in orange color in the standby state?
NO
YES
• Is the STATUS indicator flashing?
YES
NO
• Is the STATUS indicator lit?
YES
NO
• Is the POWER indicator lit in green with POWER ON?
YES
NO
• Peripheral circuits are out of order around the cabinet switch, remote control, remote control light receiver, and
CPU.
4-1
• The POWER cord is disconnected.
• Problem in the power supply.
• The cable (POPM) is disconnected.
• Fuses (F3100 to F3104) of the MAIN PWB have blown out.
• Failure in the CPU peripheral circuits of the MAIN PWB.
• Clogging around the air filter.
• Deviation from the working range and the temperature-condition range.
•The cable (bimetal) is disconnected.
• The lamp fails to light.
[Flashing at the intervals of once every 12 seconds (6-second ON/6-second OFF)]
• The filter cover or the lamp cover is dislodged.
[Flashing at the intervals of 1 second (0.5-second ON/0.5-second OFF)]
• The fan is stopped due to the fan being out of order or intrusion of foreign substance.
[Flashing at the intervals of once every 8 seconds (4-second ON/4-second OFF)]
• The cable (POLM) is disconnected.
[Flashing at the intervals of once every 12 seconds (6-second ON/6-second OFF)]
• The cables (POF1, POF2) are disconnected.
[Flashing at the intervals of once every 8 seconds (4-second ON/4-second OFF)]
• The cable (POMK) is disconnected.
[Flashing at the intervals of 1 second (0.5-second ON/0.5-second OFF)]
• Lamp is out of order.
[Flashing at the intervals of once every 12 seconds (6-second ON/6-second OFF)]
• The total lamp lighting time has exceeded 2000 hours, or the data are destroyed.
• The lamp's life has expired. (The STATUS indicator is lit in red.)
• Failure in I/O PWB and MAIN PWB.
• The cables (POMI, POXV, POXT, PORX, POGX, POBX) are disconnected.
• The LC panel is out of order.