How can I fix the iris problem on an NEC PA500 projector?

SOURCE: Text appears fade & sometimes brightness is found high on screen.

Sorry to disagree, but the tube itself is rarely the problem. Since this appears to recover somewhat, I would first search for poor solder connections at the driver transistors on the pc board that resides on the neck of the tube. If the connections are sound, the next probable solution would be to replace the driver transistors. Check also for poor connections on the main board around the flyback transformer area.

Please note that there are potentially dangerous high voltages present even with the unit unplugged. If you have no experience working on these types of units, please seek assistance from a service tech.

Thanks,
Dan

SOURCE: i want to purchase this

These projectors use your SVGA output and will work with any computer.

SOURCE: When turning on the projector it shows the Optoma logo but will not boot to the home screen. Is there a way to reload the home screen software?

Depends on the model. If you saw a little fan, then there is a fan problem. There might be 3 fans. 2 square ones and one blower fan. Look for plugs with 3 wires(red/white/black or red/yellow/black). Those will lead to the fans from the mainboard. Occasionally the fan will spin but the tachometer lead will stop reporting the fan status and the projector shuts down. To being with I would clean out the projector fans and ducts thoroughly. That may clear up the issue. Otherwise there is a button press sequence to enable the service menu, but you cannot upload new firmware without special optoma software that isnt available. Another possibility is you have failing filter capacitors in the power supply. Be careful poking around under the hood. There is lethal high voltage possibly stored even when unplugged.