My Optoma HD70 projector began flickering and flashing magenta and green (similar to what you see in this YouTube video . At first, I assumed the issue was with my lamp, but after replacing that, I realized that it was more complex. After doing some research, I concluded that the likely culprit was dust inside the projector's body, possibly around the color wheel. Unfortunately, since the projector is nearly four years old (two years outside of Optoma's warranty), the cost to have it cleaned by Optoma is $110, plus I'd have to ship it off for a week or two. No dice.
So what's an enterprising young technology enthusiast to do? If you guessed "break that sucker open and clean it himself," then I like your enthusiasm! Now I'll show you how!
Before you begin, find yourself a clean workspace that you don't mind coating in dust and gather your tools. You'll need some needle-nose pliers, a small Phillips-head screwdriver, a can of compressed air, and some Q-tips.
Step 1: Step 1: Remove the Lamp
Begin by carefully removing the lamp. Make sure your projector has been shut off for a sufficient enough time to cool down (the warning label says 30 minutes), so that the lamp doesn't explode when you remove it.
Loosen the two screws on the lamp door. You don't need to remove them completely.
Next, loosen the two screws on the lamp assembly. Again, these will not come out completely.
Then, grab the metal handle on the lamp assembly and pull directly up. Set the lamp aside in a safe place, as it is very expensive and you like it a lot!
Step 2: Step 2: Remove the Faceplate
Next, you'll need to take off the faceplate. You'll want to be careful here, as there is a wire connector for the IR port (or is it an RF port? Either way...).
First, remove the three screws attaching the faceplate to the body.
Then, gently pull the faceplate straight out from the body, and angle it so that you can see the wire connector inside.
Gently pull the plastic pieces apart and sit the faceplate to the side.
Now you have a faceplate-less projector. Put on the lens cap to protect it from all the dust and metal thingies that are jeopardizing its integrity.
Next, you'll want to remove the screws that attach the base to the lid. And be sure you're grouping your screws in some kind of organized fashion. It'll help immensely when reassembling.
Step 3: Step 3: Remove the Lid and Backplate
Next, flip the projector around so that the backplate is facing you and remove the corner screws. You'll also want to remove the bolts around the VGA port. I told you you'd need those pliers!
Now, flip the projector back upright and remove the lid. You'll need to pull it straight up, as there are posts attached to it that you don't want banging into the fragile silicon inside. When you lift the lid, do it gently and slowly, as there is a ribbon cable attaching the controls on the lid to the main board. You do not want to damage this! Lean the lid back and gently pull up on the ribbon cable. You'll also want to pay attention to its orientation (blue tip facing you), as you'll need to put it back in later. Once the ribbon cable is free, set the lid to the side.
Now, you'll need to remove the backplate in order to get to the board. Since you already removed the screws at the end of Step 2, this will be easy. Just pull gently and make sure not to break any of the ports on the back, or the metal pieces on the top.
Step 4: Step 4: Remove the Circuit Board
Now it's time to remove the main board and get your hands dirty... err, dusty. There are 5 screws attaching the board to the casing. You will need to remove them.
After all 5 screws have been removed, you'll want to pull the board straight up, as there is a perpendicular connector below that holds it in place.
Now comes the intricate part. You have to detach each of the plastic wire connectors from the board. You may want to skip this step unless you absolutely have to remove the board completely. I did, as my previous attempt at cleaning without removing the board was unsuccessful.
There are 8 plastic wire connectors attached to the main board, 7 on top and 1 on the bottom. Fortunately for your sanity, they are all color coordinated, so reattaching them will be easy. Even so, try to keep them in place to aide in this process. Gently pull them out from the board using your needle-nose pliers (or forceps, if you have them).
Next, remove the screws and the protective plate from the lower board.
Step 5: Step 5: Clean It Up!
Now you have a mostly naked projector and it's time to blow it out! Wait... that sounded dirty. Anyway, now you'll want to use the compressed air and clean out every bit of dust from the inside of the projector. I'm serious about that last part - every bit of dust. I had to do this process twice because I was not meticulous enough.
After you've cleared the innards of vorpal dust bunnies, it's time to break out the Q-tips and get in between the crevices. Pay particular attention to the fan and the color wheel, as these are likely the cause of your problem.
Step 6: Step 6: Reassamble and Test
Now, it's time to meticulously reassemble. Go back through the steps backwards if you need to. If you end up with extra screws, you probably did something wrong. This is a very delicate process, so make sure you're careful.
Once you're all spick-and-span put back together, you'll want to test it out. For me, this was the most nerve-wracking part, as the symptoms never showed up until about twenty to thirty minutes of use, so I nervously watched the screen and my clock while I hoped that everything went well.
If for some reason your projector does not power back on, just relax. It's likely that you slipped up in your reassembly and you can fix it. I had an issue where the faceplate was not reattached correctly and the projector wouldn't power on as a result. Just remember to take it slow and don't get frustrated.
I hope this Intructable helped someone. I know it's awfully esoteric, but I would have liked to have it while I was going through this (it would have saved some time and heartache), so I felt obligated to post it. Anyway, the projector is running great and I saved myself a healthy chunk of change, so I'm happy!