I need some advice about changing a color wheel. First of all I'm not really sure it's bad. While the set was running the raster went dark for all video inputs. I restarted it a couple of times and I could see the lamp light, but the raster stayed dark. I tried again to repower the set, but even the lamp stopped coming on.
I thought it must be time for a new lamp.
I removed the lamp, defeated the interlock switch and repowered the unit. I wanted to see if the color wheel would turn with the lamp removed. It doesn't. Does anyone know if this is a valid test to verify operation of the color wheel?
If I do need to repalce the color wheel, does replacement lead to any other alignment issues.
I'd appreciate some technical advice. It's been a great TV and I'd like to keep it running.
It doesn't sound like a color wheel issue. The last time I heard of this the analog board had failed. The DVI input would work fine, though. If it was the color wheel it would make a high pitched sound or simply fly apart. You may have killed the lamp by unplugging, which doesn't allow the lamp fan to cool the lamp properly. Also, re-striking a hot lamp can kill it. It's a projector and doesn't respond well to such treatment. You probably need another lamp at this point. Put your spare in and power up with the back off and see if both fans are working. You can hear if the color wheel spins up to speed. It doesn't sound anything like a fan. You can also hear a color wheel kick off at power down. The fans will continue to run another minute. If the screen stays black with the lamp on it's an input failure, not a light engine failure. The analog board is the actual board you connect RCA and component cables to. They have been known to fail and cause a black screen while the lamp is lit.
In this case, I was using the DVI when the screen went black. I could see that the lamp was lit. I waited 5 min after the cooling fans stopped before removing the lamp, but I agree with you the lamp may have failed coincidently. I'm ordering another lamp.
I don't hear the color wheel spin up even with the old lamp in place. The manual seems to imply the color wheel motor doesn't require a functioning lamp?
Looking through old messages I've learned lots from "fyi". I should have been vacuuming and should have had a spare lamp on hand.
My real concern is a DMD failure. If the DMD is bad I assume fixing it is almost as expensive replacing the set.
I really liked the Samsung, but its hard to be loyal when the $3200 set didn't last three years.
I appreciate fyi's help very much. Your suggestions really help demystify this technology.
Well...I carefully put every back together. Listening closely; I do hear the color wheel spinning.
The new lamp I ordered arrived today. I installed the lamp and just as I feared it won't light.
I measured voltage going into the ballast; CN2 is 5 Volts and the there's 380 vdc across CN1. Since the lamp doesn't fire, the manual says replace the ballast.
I could purchase a new ballast, but I'm still concerned that I have an unreliable DMD board. I'm always connected via the DVI port. Every since I've owned the set it would occasionally lock up. The screen would freeze in a black and white somewhat negative like image. Simply turning the set off then on would always restore the picture. I thought it was an inconvenience, but didn't think it would turn into a total loss.
I followed fyi's link for a DMD board on Ebay, but the guys no longer there.
New lamp + ballast + DMD maybe a little cheaper then a new set, but seems like quite a risk. Do you think I should go for the ballast? Any other suggestions would be appreciated.
Ballast received, but unfortunately didn't do the trick. Since the 5vdc and 380vdc signals are present, one of the other signal leads from the DMD must not be right. The DMD to ballast cable looks OK although the connects seem fragile. I'd have to dig deeper to check signals on each pin. Do you have a source for a DMD? My model number is HLN467WX/XAA.
I may have to bite the bullet and replace this set. I really like the Samsung DLP, but I'm feeling a little burned right now.
Have you seen the new LCoS technology? I understand the specifications for contrast ratio isn't very good; maybe 1000/1. The Sony units I've seen sure look good. And the sales folks really talk up the feature of no moving parts.
The DMD wouldn't keep it from lighting up. Only a thermal protection circuit or a flakey power switch would interrupt the ballast and lamp combination. Strange..... A service call may be beneficial. They might have some knowledge and/or used parts. It could still be much cheaper than a new set.
Alternatively, the SXRD's are quite nice, but quite expensive too. Contrast is comparable. The new set designs removed the bulky side speakers.
All's well that ends well. It took a little time, but Samsung really came through for me.
When the service tech (Nick from T.C. Service, Renton WA.) came out he found the digital board was bad; which kept the lamp off. Then he found the DMD board was bad causing the screen to freez. I called Samsung and negotiated; I'd pay for labor if they would cover the parts. After I faxed receipts, they agreed, saying this set had more problems than normal.
Also, when Nick fired up the set for alignment he noticed a distinct high frequency noise coming from the color wheel. I couldn't hear it because of all my years with rock and roll, but he was positive the color wheel needed to be replaced. (My wife confirmed later; she was surprised and happy that she could watch the set without that annoying screech)
Now that it's over, I'd say it was a positive experience. The set is working as good as new and I sure learned a lot about DLP. It took some time, but I was especially happy that Samsung stood behind their product. Every since I purchased my set, I've been pointing people to Samsung DLP technology. I even convinced my son to by a Samsung HDTV. I would have felt awfully stupid if the sets wouldn't last more then a few years.
Thanks so much for your coaching. It's really great that you're willing to share your knowledge. Samsung's back at the top of my list because you helped show the way.
