Looking for Guidance

[Rip01]

Was up guys need some help bypassing the ballast in my Nec vt580 Projector. Trying to change it over to a 100w LCD to improve the life time of the light source from 2000 hours to close to 10,000 hours, and save some cash. After a few months of trying to find Information or a guide on how to bypass the ballast. I gave in and got my hands on the Service Manual. Now I been studying the schematics, but most of it goes above my head. I think I need to make the modification in the IC3005 but frankly I am not sure. The board and the ballast use serial communication to talk to each other. And that chip (adm3202arnz http://www.analog.com/media/en/technical-documentation/data-sheets/ADM3202_3222_1385.pdf ) appears to be the hub between the MB and the ballast. During my research I came across crazifunguy who managed to do it, with another projector with serial communication. Check out the post http://www.diyaudio.com/forums/diy-projectors/172262-digital-ballast-bypass-expirimenting-2.html. is a cool read. I also came across another guy who build a Ballast emulator. http://uvdlp3d.blog.hu/2017/01/13/the_beginning_790 now I don't have all the cool toys or the knowledge to pull something like that off "Yet" but I can follow directions, if some one can tell me what parts I need and how to wire them together. I am sure put it together. At any rate any help would be greatly appreciated. Here is the link to the service Manual http://www.analog.com/media/en/technical-documentation/data-sheets/ADM3202_3222_1385.pdf

 

[kellys_eye]

According to crazifunguy...

By cutting the trace from the pic to the buffer and connecting the buffer pin to the buffer ground the projector stays on....

SUCCESS!!

 

[Rip01]

@kellys_eye Yeah he got his success by hacking the ballast. Only down side for me is that my service manual does not come with the ballast schematics, and his link to the IC is dead. So I can't see what he did to get an idea of what i need to do. My idea was to Follow Rxd signal from the lamp_Det and make the modification in the IC3005 chip. to fool the the projector to thinking every thing is fine. But I am not sure if my approach is going to work. Basically with my skill level is nothing more than guessing game for me. Part of the reason I am turning to more experience people than me for help.

 

[Rip01]

I just realized that I posted the wrong link to the service Manual. Sorry about that. http://www.filedropper.com/vt48-580

 

[kellys_eye]

You're approaching this from too 'deep' into the electronics. Instead of looking at the signals post-processing (PIC output) you need to be looking at the way the error (lamp detection) is done - according to the manual these are 'bi-metal', 'suction temperature' and 'exhaust temperature' outputs.

These will all be simple devices - a bi-metal strip and a couple of thermistors . These can be 'faked' by hard wiring or replacing the sensors with fixed resistances and fooling the processor into believing it has the correct signals.

 

[Rip01]

@kellys_eye Thanks for taking the time to help me out. I will look in to you suggestions