At it again: Infocus LP280 Projector Lamp Hacking

Hardware related mods, hacks, questions and ideas.
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At it again: Infocus LP280 Projector Lamp Hacking

Post by Jarod » Fri Mar 22, 2013 3:19 pm

I'm trying this again, Hacking an Infocus LP280 projector to use a high brightness LED array as a bulb instead of the ugly, expensive old xenon bulbs.

Be very cautious, projectors have extremely high voltage inside them and will cause serious injury if handled wrong. I have burned my skin, lost control of my muscles and probably came awful close to stopping my heart before I started playing it safer with these.

ALWAYS insulate yourself, have a piece of wood as a workbench, or plastic or something non-conductive.
NEVER use tools that are not insulated to poke around with, leathermans, pliers without plastic handles, etc.

Ok, on to the cool part.
There is a 3 wire plug that tells the lamp power supply to power the lamp up, i'm hoping that one of those 3 wires is feedback to the board and with a quick jumper wire we'll be in business.

heres some photos showing what i've found so far.
Projector model LP280
Need something shoved in here to allow lamp to power up when there isnt actually a lamp installed.
Circuit board. Interesting part circled
Lamp. conveniantly labeled. when this 3 wire connector is unplugged the power supply makes no noise or high voltage. this is our 1st target with the multimeter

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Posts: 189
Joined: Sat Dec 11, 2010 12:34 am

Re: At it again: Infocus LP280 Projector Lamp Hacking

Post by Jarod » Sat Mar 30, 2013 12:45 am

Found it. now I just have to come up with the cash to get this done and returned.

Here's what i found:

Here is the Ballast for the old bulb. contains very high voltage parts. it receives around 380 DC Volts from the main psu.
I noticed where the "lamp" Connector found in the first post there is 2 optoisolators. notice the little chips out of the side (Dimples, holes, whatever you want to call them), That marks pin 1 of the optoisolator. A quick Google search turned up a datasheet for this opto, found out pins 1 is on the input side.

An optoisolator essentially is a led and a photosensitive transistor. when power is put across the input (LED) side the transistor turns on and allows power to flow through the 2 output pins.

Now back to those pin markers. note one is installed in one direction and another is installed in the opposite. the one with the dimple towards the white connector is sending something from the mainboard to the ballast. the one going the other way is doing the opposite. sending something from the ballast to the mainboard. see where I'm going with this?

A quick probe with my trusty multimeter later and find out the green and white wire need to be shorted to make the mainboard think the ballast has powered up.
One super nice thing about this projector is the ballast and psu are very separate. I removed the entire ballast after this. which makes a very nice space for a 36V power supply to light up one of these: ... ND/2798352

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