Instructables

Step 2: Electronics involved

The first step was to fool the electronics into thinking the lamp is present so that the projector will start operating properly and get rid of that automatic shutdown. A few Google days later I came across a French site on the very same subject. It turned out all I had to do was to find a logic signal that was up (5V) during the first two minutes and down (GND) just before the LED missing indicator turned on. I found it eventually, using my multimeter. By pulling this signal up (a simple wire jumper connected to a 5V source I found on the board) it started normally thinking the lamp was present and on. I connected a laptop to it and checked that the movie was playing by looking into the lens while holding the same flashlight inside the projector. Yes! I was glad I did this, I’m not that experienced in electronics and I feared I may end up stuck at this stage.

 
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RENUKA.NAVI4 years ago
thats aasome from akash
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claudiopolis (author)  DELETED_jaapie914 years ago
I'm sorry but I haven't made any photos of that wire and its position. I must have been too happy I made it, I don't know. But unless you have exactly the same projector, my photos would be useless as each brand has different boards and the bridge must be made in different places. First, find a gound trace on the board. Then put the other probe of your multimeter (set to DC) on the power connectors coming out of the power supply. You are looking for connectors with thin wire, not the power lines. These thin wire connectors there are ony two or three) provide feedback to the power supply. Start the projector and wait until the "lamp missing" is lit. Then measure and make a note of all the voltages on those connectors. When done turn the projector off and on again and measure all those voltages once again. You need to get the measurements BEFORE that "lamp missing" LED lights up. It may take a few attempts to get them all measured. Then simply compare the results. You'll see there is one wire that changes state just before the "missing lamp" lights up. It may have 5V before and 0V after or the other way around. In my case it was 5V initially and 0V (ground) a couple seconds later, just before the LED lit. I then randomly measured the voltages on the board and found a steady 5V line somewhere then just simply connected that line to that pin with a wire. That did the magic trick, the LED wasn't turning on anymore and the projector booted properly.
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claudiopolis (author)  DELETED_jaapie914 years ago
Sorry for the missing photo with the bridge then. My projector is packed away right now as my room is now a nursery :-) So no chance of opening that projector again any time soon. Finding good leds is hard and costly. And when dealing with high power, cooling is A MUST. Given the very confined space available for the bulb, this is one hell of a project. I wish you good luck. Maybe you could post your experience here on Instructables, I would love to see your progresses. Do you have the original bulb casing? I bought this projector without any bulb and making a proper casing is the most difficult part for my v.2.0 lamp version. The anchor points are all over the three axis.
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claudiopolis (author)  DELETED_jaapie914 years ago
Be careful with the multimeter. If you fry the logic board then this is it. Nothing can be done anymore (at least at my level). So please put the beamer aside for a couple of days, I'll try to find some time to open it again so that I can make a photo of the bridge for you, during this weekend. Be patient, I'm swimming in baby powder and dipers over here! :-) The little guy's three weeks old now. The original bulb case is gold. At least to me it is. If I had one I would try and retrofit a xenon car bulb inside that original casing and reflector. I found a tutorial on the net somewhere on how to do that but you need a lot of patience and a dremel. I have neither of those :-) The original casing is gold because it can be measured and in case you want to make a non-destructive LED conversion (like me) it tells you how to make the LED housing and the mountpoints precise location. So hold on to that bulb case. Or give it to someone who needs it. Like me :-))