sharp lcd projector auto shutoff

[kahurt]

I have a sharp XVZW99U lcd projector. I bought it new two years ago. when the lamp burned out (which was very soon) I was sickened when I found out that sharp wants $350 dollars for a 1400 hr. lamp. When the lamp went out the entire unit shutdown and there is somekind of shutoff system that wont let the projector run without the lamp. My question is . Is there a way to rig up a less expensive lighting system for this projector and how do you get the projector to think it is the sharp lamp?

[diylabs]

The answer is basically yes, but there are some catches ...

I've rigged a Panasonic L592 or something like that to use our 250w metal halide HQI light source once. It worked beautifully. The only thing I had to do was to make the projector believe that it had the original lamp inside of it turned on. The way I did this was to locate the 3 wires that went between the ballast and the main board and to use a small resistor to short out two of the 3 connections - PRESTO! It worked fine, but I sold the projector before I had the mind to take pictures of the results. With that particular projector, it worked just as good as when it had the original lamp in it - I was very pleased.

Now I've got a Chisholm projector that has a 4-wire connector between the ballast and the main board and I can't figure out what it takes to trick this projector. I assume that there is some logical combination to tell the projector what the lamp status is, but I don't know what that would be.

Does anyone know how to trick a projector with a 4-wire communication bridge between the ballast and main board into thinking that it has its lamp turned on?

[kahurt]

the original lamp was a 340 watt metal halide . If i rigged up your lamp could i use the ballast in the projector or would i need the one that comes with your lamp?

[diylabs]

The lamp voltage is what is most important in this case. In general, you should use a ballast only if it was intended for the lamp you'll be using with it. I doubt that our 250w HQI or any other metal halide would work with your current ballast except for the lamp that was made for your projector.

[kahurt]

also would the ballast be easily reconized in the unit ? Is the size of the resistor important ? I will take some pictures when I get the projector opened . Maybe you could help me identify the wires to short. thanks

[diylabs]

The ballast is usually a separate circuit card with medium/large coils and or capacitors on it. You'll recognize it easily since it is the circuit that is directly connected to your lamp assembly. Don't touch the connectors for the capacitors - could cause a ZAP!

Assuming that your projector has the 2 or 3-wire connectors, then yes I'd be happy to help you, though my method is basically trial and error. Initially I just used a wire/jumper to short the two leads, but then someone recommended that I put a small resistor in there to manage current. You could use anything from 10-100 ohms probably ... it doesn't take much.

[kahurt]

When i had the cover off before I noticed a label that said to service make sure to first turn off lamp first. Maybe there is a switch somewhere that will allow the unit function without the lamp. Also just a note of thanks for all the information posted here and on your website . two years ago when i first tried to buy a replacement lamp from sharp and found out how expensive it would be I decided that there had to be a better way . back then i found no information on the internet. execpt some rippoff about making a projector from a small tv. of course i was despirate enough to be ripped off. I had my hope restored when I came across this forum and then your website. I am telling all my friends about the doit yourself labs website. thanks

[diylabs]

You are quite welcome, and thank you very much for your kind words - that makes it all worth while for me. And don't worry about being ripped off by those "make a big screen from a small TV" offers ... I got burned too, but that's what got me started in DIY projectors. I think a lot of us have been burned on that same deal. Oh well - a $15 lesson in DIY projection

[kahurt]

here are some pictures

[kahurt]

another pic