Home Theater Forum and Systems banner
1 - 9 of 9 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hi, I have a Optoma H78DC3 projector and, while in use, I heard a fairly loud pop sound and then, the color went green - yellow, then the lamp shut down. When I removed the lamp to inspect the damage, I noticed that the color wheel partially broke (pieces of glass, missing a color segment). I took the whole projector appart in order to get to the color wheel connector and removed the color wheel assembly.

During the process, I had to remove the heat sink of the DLP chip, but the whole chip came out, exposing it to open air. I was very careful to put it back without moving dust etc.. but that was not supposed to happen.

Can not having been in a white room during this incident cause my projector to be toast? (cannot test it until I put a new wheel in there) - I heard the lamp will not initiate without the wheel in and spinning properly.

Is it worth replacing the wheel?

Any experience on this subject would be great! I currently reassembled the whole thing (so I would not forget the steps) and now need to order the part.

Best regards,
DJT.
 

·
Premium Member
Joined
·
3,374 Posts
Seeing that your Optoma isn't even 1080p, and is low lumens, I think you now have the perfect excuse,if you need one, to replace it with a more up to date one. Just my 2 cents...:T
 

·
Plain ole user
Joined
·
11,121 Posts
The main problem will be re-aligning the chip. It is a tedioud trial and error process if you don't get it right back where it was, which is very difficult. The air will hot harm the DLP chip. They are very durable actually.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #4 ·
Just what I was fearing.. and the chip is literally the LAST component in terms of accessibility (everything must come out before gaining access to it...really). I guess I will consider the upgrade idea even if I was very happy with this projector and have a spare lamp ($$$). I'll give the fix a try with a Chinese aftermarket wheel (30$US - the original is 100$). At lest to see if everything else is ok; including the chip positioning.

Considering the replacement option, yes the lumens are low on this model, but the image is impressive and the unit is literally dead silent. They sell Optoma projectors at Costco for around 1500$ (in Canada). How do these compare? Are we in the same ball parc regarding quality? Did the technology really come down in price that much or are these toys? IMHO, any projector that comes with a built-in speaker is more of a toy...

Any opinions would be great as I did not own enough projectors to use anything else than the H78 as a ref.

DJT.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
BTW, while the Chip was held in a rubber type holder and secured with 2 tiny metal tabs (very flimsy), there were adjustment screws on the lens assembly. Would these be to adjust the later wrt the chip by any chance. In that case, it would make calibration much simpler and logical... just an idea. DJT.
 

·
Premium Member
Joined
·
3,374 Posts
Well your PJ came out in 2005, so have they come along way since then? I would say yes. Your Optoma retailed for $3999 and if you were to spend half of that on a new one you would be happy with the performance. Check out the Panasonic AE-8000u, You cant go wrong for the price.
 

·
Plain ole user
Joined
·
11,121 Posts
BTW, while the Chip was held in a rubber type holder and secured with 2 tiny metal tabs (very flimsy), there were adjustment screws on the lens assembly. Would these be to adjust the later wrt the chip by any chance. In that case, it would make calibration much simpler and logical... just an idea. DJT.
Lens adjustments may allow horizontal and vertical positioning, but rotation has to be right on installation. There is no way to get to it to adjust it without taking the whole thing apart.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #8 ·
Not easy... I live in Sao Paulo, Brazil where a toaster or microwave costs a fortune (forget about projectors). I am going to Canada next week, so I will not have the chance to order a part and test prior to having the opportunity to buy a new projector.

Has anyone ever order replacement parts from Guangzhou Yue Yu Electronic Co., Ltd. (China). I was considering getting the replacement color wheel from there as any OEM part might be overkill considering the age of the projector. Also, if I could sell my new spare lamp (and the one actually in there), I could amortize the cost of a new projector. Any idea if there is a demand for these (I think they are used in other models of projector).

Thanks,
DJT.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #9 ·
Optoma ColorWheel replacement

UPDATE:
I got my aftermarket color wheel from China. It is not identical as the center metal ring is a quite smaller, but the diameter, sync, segments, etc are all identical.

I went ahead and mounted it into the projector (big job). When I finally tested, it did not turn. All that happened was a slight smokey smell and I shut it down. I then noticed that the flat cable ribbon cable had literally melted. Not good. I dismantled it and noticed right away that the aftermarket wheel has its flat cable attached via a PCB glued to the motor rather than the cable directly glued onto it. This makes for a fatter design which did not clear the metal bracket used to mount the unit, and hence, shorted both extreme solder balls. Not impressed!

I replaced the burnt (and severed) wire with a barnacle and after much fiddling around, I ran a test. Now, the auto test process starts, the wheel starts to spin and the bulb starts for 2 seconds, then goes off and the projector goes into Light Error Mode (blinking red LED). On top of that, the wheel make a very loud high pitch noise.

What is going on? Did the short damage the control circuit? (by some miracle, does not look like it). But could the bearing be bad on top of this PCB soldering issue?? This is becoming quite the adventure. Not easy to resend the wheel for replacement as I am charged 30$US for shipping one way and 50$ tax here in Brazil.

Could the noise come from a defective wheel and the extra resistance prevents it from getting to the proper speed?

I'm loosing hope. :huh:

Option 2: Sell it for parts + 2 lamps in their holder (one is literally new, the other has little hours on it).
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top