Fix A Projector On The Cheap

[j] sent in this nice writeup on how to revive a dead projector. he managed to pick one up for $20 that had a broken bulb. While the prices of bulbs have come down considerably, they can still be a couple hundred dollars. Being resourceful, he decide to just use a halogen bulb that he picked up at his local big box shop. In the photos, he’s using a 50w mr16 bulb. The results really aren’t too bad. Especially considering that his cost for the entire project is now roughly $25. He does, however suggest that a 100 watt bulb wouldn’t be a bad investment.  His projector seems to need some cleaning and adjustment in the lenses as well, but for $25 it isn’t too shabby. We’ve had this submission for a bit, but it didn’t have any pictures of the projector actually working. During our conversation, we may have possibly suggested a picture we’d like to see. You can find it after the break.

We did cover a very similar one last year, which had the driver integrated into a custom bracket, but the project page seems to be gone. There is also the possibility that the projector you get doesn’t just have a bulb problem. Sometimes it is the polarizer that needs replaced.

Egotistic? Never.

46 thoughts on “Fix A Projector On The Cheap

  1. Careful going out and buying a bunch of busted projectors, most of them will not turn on if the bulb doesn’t light. I bought a projector off craigslist for $10 a few years back and couldn’t find the optocoupler that tells the electronics that the bulb has lit and that it can power on.

    Most projectors are stuck in a non-operating state if the bulb isn’t running, some furthermore have optical detectors to determine if there is actually light being emitted by the bulb. YMMV

  2. Nice, also you can replace a DLP color wheel if necessary.

    I am currently repairing CRT rear projection TV’s, you can get them free many times and repair for under $100 in parts :)

  3. For those looking to “trick” a projector into thinking that the bulb is still there, so you can replace it with a cheaper setup, this is the “famous” post on diyaudio that discusses the issue.

    Essentially, the ballast has a logic line that indicates if the bulb is lit. In the case of the link, tying it straight to ground (on the safe side of the opto) forced the unit into thinking the bulb was always lit.

    I’ve been thinking about doing this to a 3LCD project I got for free, with a blown bulb & ballast, and retrofitting 100W worth of high power LEDs in it’s place.

  4. @nubie
    “Nice, also you can replace a DLP color wheel if necessary.”

    Did a quick search of the article but did not find the word “color”. Please more info on color wheel replacement – especially where to get parts! Have a very expensive projector sitting here with a dead color wheel and I’m too lazy to drive the 40 miles to the nearest authorized repair facility.

    Don’t buy InFocus – their customer support sucks (for the consumer) and the two InFocus products that I have purchased made it through the first bulb and died on the second bulb. Not sure if it is due to the fact that their factory bulbs explode at the end of their lives or what. Their customer support was absolutely uninterested.

  5. Amen Greg- I’ve got a dead Infocus 4805 that blew (actually exploded scaring the ever living crap out of me) after only 2000 hours (with scheduled maintenance). You can’t even buy parts for it yourself- I had a buzzing colorwheel issue with this before the bulb blew itself to pieces.

  6. @dave
    Yerp, both InFocus projectors blew their lamps – *pop* – run for the mercury free zone! On one the color wheel is completely dead – vibrates real bad on startup and sometimes gives really whacked video, most of the time it refuses to fire up. The second, a 4805 as well, popped a bulb and now about %10 of the projected image on the right side is “dim”. Ok for SD but sucky for HD. And worst of all the InFocus support folks neglected to return my emails and when I called they were rude and did not care that they were losing a customer.

    @nubie – thanks! I just never thought replacing the color wheel was something that a user could do (special tools, etc.). I took this one into a non certified local repair guy and he serviced it but could not do the color wheel as he had no source for parts (not being an official InFocus repair guy). I’ll take a look online though! Thanks!

    Thinking of replacing the InFocus projectors – can anyone recommend a bullet proof, well supported, awesome looking “full resolution” HD projector? Currently using component but HDMI is not out of the question in the future. Probably something in the < $5K range…

    I know that some of the pico projectors use three bright LEDs. I was hoping that someone would come out with a "regular" projector based on the same idea that did away with the color wheel. No color wheel and LEDs would remove the most problematic parts!

  7. googfan is right, it would be very very yellow. Color temp is measured in degrees Kelvin, a halogen bulb is 3-4,000 and white is somewhere around 5,500, so you want to get a good bulb, you can put in another Discharge lamp for $30-100, I would look that direction.

    @ Greg:

    I know that there is also a laser DLP that looks very interesting to me, I don’t know if LED or Laser is better, but either do away with the bulb and the color wheel. I think Mitsubishi has some Laser DLP rear-projection TV’s out now.

  8. @nubie
    Oooooohhhhh laser! Anything with a laser has to be cool! Can it cut metal and engrave too? ;) You’d think a laser would allow a super high contrast ratio – worth looking into! Thanks!

  9. @nubie
    Did a little intarweb searching and it sounds like we are not too far off for a laser DLP projector – sounds like laser RPTVs are already here – its just a matter of time. I guess I’ll limp on with the 4805 or try to get the nicer one fixed – but I’m saving my $$$ for a laser DLP!

  10. The project page for the other article is still there. I know because its my project and article. Due to changes in my site format the link is no longer just recklessphilosophers but the first or second commenter as the link correct. Its not gone, just moved a bit.

  11. @nubie
    Sigh, found no place that offered InFocus color wheels for sale and then found a DIY page that said InFocus does not sell parts outside of its service network. They recommend buying a broken unit off of ebay with working color wheel. That sounds like a good time…

    InFocus sucks

  12. Before large LCD’s and thin TV’s were really on the market I built a projection television cheap. I should say I had help building one.

    It involved an overhead projector like you see in high schools. I picked one up off eBay that got modified to use a light from Home Depot. Cut a hole in the side for a fan to get rid of some of the heat the new bulb made. Similar to something like this:

    Then I bought a cheap InFocus LCD projection panel off eBay for under $50. Looked similar to this:

    So, whatever is displayed on that panel gets projected on the wall.

    Kind of bulky, kind of ugly, but was cheap and huge.

  13. @nubie
    Thanks, wrong projector though, nothing but lamps for the 7205 :( Watching the 4805 right now – but I learned that its “light tunnel” is likely collapsing causing the dimming. I’ll give the service place a call next week to see about getting the good one in and save my duckets for a laser projector ;)

    Once I get the good projector fixed maybe I’ll give the 4805 a little open heart surgery. The 4805 is a great projector but the 7205 is much better ;)

  14. I have done approximately the same thing with a DLP, except the bulb I chose was from an overhead projector (the type high school math teachers love). At first I used the diode and resistor salvaged from the overhead, but i have finally settled on using a light dimmer for control. The first bulb was nearly burnt out, and when I replaced it with a new bulb the projector went black and white until I was able to dim it (I’m slightly curious as to why, but really don’t care). Now the bulb runs cooler, and believe it or not the white balance is not such an issue. It is the slightest bit warm (color wise), but when you measure your screen size in feet and not inches (practically for free) who is going to complain?

  15. blizzarddemon,

    You have it backwards. Any incandescent lamp (hot glowing wire) will put out a much more full spectrum than a metal halide. Ever stand under a mercury vapor or sodium vapor streetlight and notice that everything seems monochrome? Same problem with halides, only not as pronounced.

  16. Hello guys !
    Can somebody help me to resolve the bulb psu ?
    In a few words :

    I have started an project that includes the replacement of the lamp from an Benq MP 510 DLP projector with an 100W LED like this one

    I have stuck on hacking the signals from the psu to the logic board . On the Lamp PSU ar etwo optocuplers , one for input signal and one for output signal. If the output singnal ( the one from PSU to logic board ) is in low ( conected to ground with an 100 ohm resistor ) then the projector starts for 1 min. I have image , I can control it but after 1 min the lights from lamp and temperature are going on and the projector is in standby. If i put the signal on high the projector does not start.

    What should I do ?

    Please , I need some advice.

    I have some pictures of the going progress here :

    but is in romanian and you need subscription.

    If anybody whant i will send the photos over mail.

    Thank you

  17. koff 100W LED /koff :)

    doesent need to be driven at even 40% power and has the advantage that the optical aperture on most projectors is identical to the emitting area.

    plus it takes 36V at 3.6A which is well within the requirements of the existing power supply if the HV ignition circuit is removed and the power supply output fed through a constant current (LM317?)

  18. @Greg, one idea i came up with is building an RGB LED “colour wheel” to replace the existing one.

    no moving parts and the diodes are off the shelf 1W RGB luxeons.

    gets around the lack of a colour wheel, plus the failure of a diode only results in a dimmer picture.

    i also came up with the idea of using a single 100W LED with carefully dremelled “interconnects” drilled into the encapsulant and 100C alloy solder + wires to detach the top and bottom thirds of the array, then a colour filter on each section.

    would have tried this but someone bought my LED off me beforehand for their project.

    besides its cheaper to buy several at a time (bulk discount) and sell them on.

  19. Seriously? People dump projectors that are fine when the bulb goes? I can’t freaking believe that, I have to see it for myself, but I doubt I ever will though.
    This kind of story is just too damn frustrating.

  20. I acquired some 20W LED’s here (basically small variants of the 100W units) for the unbelievable price of £10 inc postage off ebay.

    At 20mA it gave me afterimages that took five hours to fully fade, so I think these are closer to 30W.

    Someone suggested to perform open-diode surgery :) on these and separate the string into two parallel strings with a common cathode. Add a red/blue filter on one and a green filter on the other, then use standard 3D anaglyph goggles to make a 3D projector on the cheap.

  21. I’ve had some less than great experiences with “knock-off” (non-oem) lamps. One died right after I installed, and the other overheated and caused a ton of other issues. I just purchased a lamp from Mendtronix for my IN38 (used to be called Projector Doctor) The lamp itself was a bit more pricey, however the quality was amazing and it came with a 4 month warranty. I’m not very technical so I would probably reach out to them or another similar company for repair services if anything needed to be fixed. Hope this helps!

  22. Projector lamp needs replacement, we should instantly check the projector enclosed instructions to ensure protection, replace the exact operating procedures; at the same time, the purchase of projector bulbs, but also what we can with the common type of bulb projector recognition compatible, which is not compatible, if selected fault lamp type, and even may even burn the projection lamp projector.

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