HD20 broken filter wheel - temporary repair
Hi. I've been buying the sub-$1000 Optoma projectors as my main TV for the last few years. First was H31, then HD70 and currently using one of the first HD20's, purchased in Aug '09.
I tend to be pro-active with maintenance, and always change the lamp at 2000 hours to keep the brightness up, regardless whether it's still working well. But last cycle on the HD20 the lamp failed early at ~1800 hours so I didn't get that option.
It was a destructive failure, i.e. the lamp glass shattered with a loud bang. I opened up the projector, cleaned out the loose glass and dust with a damp paper towel, then vacuumed the remaining debris using a HEPA filter (there is mercury in those lamps, you don't want to get that airborne...)
Anyway, long story short, after all that cleanup I put a new lamp in and it ran for another 1230 hours but on Friday the projector started making a loud noise and the colors were out. When dismantling the projector, it was obvious one of the red segments detached from the hub of the color filter wheel, it was laying on the bottom of the case.
I'm assuming it could be collateral damage from the 'impact' of the previous exploding lamp, although from the amount of posts to this thread it seems to be a common failure as the HD20 ages.
Of course this all happened on a Friday night just when the new TV season is getting underway, rather than over the summer when there was nothing worth watching for days on end, so the wife isn't happy... So after looking through this thread, I decided to try fixing the wheel temporarily - Optoma aren't open at weekends so earliest I could even order a new filter wheel is next week.
I got some JB-Weld high temperature epoxy from the hardware store, and used tiny, tiny amounts to carefully reattach the filter to the hub, using tweezers and a small-bore syringe to precisely place the glue.
After curing overnight, I reassembled the projector and the filter wheel ran for a few minutes, followed by another failure. Of course, I assumed my repair was bad so I left it for the day, figuring I was out of luck until I can get a replacement wheel.
But last night, bored with no TV to watch, I decided to dismantle the HD20 again (this was getting annoying, the projector is ceiling mounted!) and actually I found that my repair was good, but two of the other segments had now detached.
They were the red opposite to my repaired filter, and the blue adjacent to that. I figure maybe I had introduced a balance problem with the repair, hence an already-weak bond had failed on those filters also.
Clearly this was a more general failure of the bonding between the color segments and the metal hub. So I decided to stress all the segments by flexing them sideways using a cotton-bud, and found one of the green segments was also getting weak. So including the first red segment, I've now glued a total of 4 of the 6 filters back on to the hub using JB-Weld - at least the glue is fairly uniformly balanced ;-)
Again the JB-Weld was left to cure overnight, and this morning I powered up the HD20 to see what would happen. Have to say, I wasn't confident at all but there wasn't much to lose at this point in the game.
But surprise - so far I've been watching the F1 qualifying and pre-race for ~2 hours and the repair appears to be holding...
Of course I wouldn't consider it to be a permanent repair, it clearly still sounds out of balance, but I hope I can get a replacement color wheel from Optoma when they reopen their phone lines on Monday...
Just figured I would post this for others who might be interested.
