I am new on the forum and new with electronics.

Recently I started a project in modding a video projector, and did so successfully, and now got another that is giving me a hard time.

It’s a NEC VP400 Video Projector that I got without a lamp and I want to put in it a Xenon Light since I have a 55W Ballast and Bulb, the problem is this.

The VP has a 5pin connector on the motherboard that goes to the lamp ballast, pin 1 is the +3V Lamp OK, pin 2 is GND, pin 3 is the signal to fire the lamp, pin 4 seems to be GND to and pin 5 I believe is ECO Mode. In the previous VP when I shorted the pins for the lamp OK signal it powered on without any problem, on the NEC it still gives a Lamp Error.

From what I found on the internet some VP’s have a Serial Communication between the motherboard and ballast, and for this reason I’m stuck. And I can’t find the service manual for the VP, because in the manual I’m certain I could find the traces for the Lamp OK signal.

Here are some pictures with the VP.

Motherboard with shorted Pin 1 and 2 on the ballast connector

Ballast with opto isolator legs shorted

Ballast with a chip for whom I can’t find any data

Another with the Motherboard and two GND’s

Pictures with the chips on the motherboard