HLR4266WX/XAA color wheel replaced, no picture

[windstar]

I have a Samsung HLR4266WX/XAA which refuses to work.

Months ago the color wheel broke and I could hear a grating noise accompanied by significant vibration, but I followed the three-flashing-lights error code and changed the bulb, then the ballast, and only then, finally, removed the color wheel and found it broken, so replaced it one week ago. Everything worked for 2 days and I thought I was good to go. I put back on the rear cover, moved it from the workbench back to the living room, and then after a couple of intermittent uses I would not get the sound that the tv is turning on, the lamp light continues to flash, and the set eventually powers off.

The amazing thing about this situation is that the lamp turns on fine, the screen lights up faintly (only white), the color wheel sounds good (smooth high rpm sound), and the set has actually turned on normally two times since I started troubleshooting, but only for a couple minutes before everything freezes (forcing me to unplug it), at which point it's back in it's funk. I now believe that the power board, ballast, lamp and color wheel are working fine, so maybe it's the dmd board or analog/digital input boards. I can't afford to spend another $400 and more countless hours in vain, so any troubleshooting assistance nailing down the problem would be hugely appreciated.

More info -

I moved it back to the workbench from the living room after this latest problem appeared, and started troubleshooting. Here's what I've tried & found -

Shorted the lamp cover switch to bypass it.

Checked lamp and DMD cooling fans - working ok.

First put back original bulb. Same result. Then put back original ballast. No change. Bulb lights, lamp flashes, screen lightens very faintly, no sound, set turns off after couple minutes.

Suspected temperature sensor. Placed room fan in back of tv in different locations. No change. Disconnected sensor to test effect, lamp does not light and get standby/temp flashing on front. Checked sensor and get zero resistance through it (normally closed?). Is this correct?

Removed light engine, took color wheel out, looks ok, put it and everything back, set TURNS ON! Get picture for about 1 minute, try to change channel, picture freezes, set frozen, have to unplug to reset. Back to original symptoms.

Remove analog/digital boards to check for damage, connections, etc. (Starting to think DMD board not getting signal to make picture.) All looks okay, replace, no change.

Back to light engine. Take out, check cables on color wheel, (don't want to mess with anything haven't messed with yet!), put back, set TURNS ON! Picture/audio shows for one minute, screen freezes, have to unplug to turn off and now back to original symptoms! Arrrgghhh!!!

And that's where I am. No idea if it's significant, but almost always when I hit the power button, the lamp light flashes twice, then stanby/temp flashes once, then it's back to the lamp light flashing. In this time the bulb lights okay. Is this normal? After 1 minute, the lamp light stops flashing, the bulb stays lit with color wheel & fans running, and one minute later everything turns off.

Sometimes, the standby/temp light does not flash but everything goes the same.

One other thing - there is a small fan on the analog/digital board, which does not run. Is this normal?

I've spent hours reading through forums and have not found any posts with an identical failure mode. This is my last-ditch attempt to rescue the tv, or else it goes to trash. Thanks again for any input you can give.

JMK

[Eddie]

Wow, so much detail! I believe it might be your DMD board. Those things rarely go bad, but if you get picture freezes, that could be the root cause of all this mess!

[windstar]

Thanks for your reply, Eddie.

Any suggestions on checking the DMD board?

I've taken off the metal cover - should I remove the heatsink on the DMD chip?

The DMD board is coming up at $180 on D-M - if I knew this would fix the tv, I would consider it, but really can't afford another failed fix!

[Angel]

Hi windstar,

Just to discard: Clean the Light engine and put it back into the TV. The TV should turn ON (since every time you took the light engine out the TV turned ON fine), then try to display the TV menu, if the menu works OK even when the picture freezes then the problem is most probably with your digital board, I think your issue is due to overheating (I'm just not sure about which board is the problem, DMD or digital).

Get back to us once you've tried this test.

[windstar]

Hi NEhelp,

I think I figured out what condition was making the tv turn on -> disconnecting the power cord for an hour, or more!

I was able to get the tv on by doing this, but if it started to refuse to turn on, and I just unplugged it for 5-10 minutes, it would stay in its failure mode.

When I did get it running I pulled up the menu like you suggested, and the menu did freeze along with the rest of the screen after about 10 minutes. Note that the Timer light would flash when I tried to use the remote after it failed, but nothing happened.

I now think it is NOT necessary to unplug the set after failure, but to be really patient (>10 minutes), and it turns off for itself.

I pulled out the light engine completely and checked for dust - none to speak of. Blew it all out with compressed air anyway and no change.

My troubleshooting so far has led me to suspect the input board(s), particularly the coax inputs vertical box, as when the tv is plugged in and not ON it gets quite warm (like it's working or something). I'm thinking when this part gets cold by unplugging the set, everything then works until it warms up again. But this is just a guess on my part.

Please let me know what I might try next.

[windstar]

Following up on my last update, I am no longer having any luck getting the tv to turn on. I suppose that whatever part was causing the previously sporadic failure, is now dead.

One test that -seemed- to impact the set was placing a room fan at the back of the set. It's not that it ran for greater than 10 minutes when the fan was present, like some have reported, but it did shut-off and then could turn back on, once or twice, which is something I had not seen since its refusal to show began. But I could not duplicate this so maybe it was just a coincidence.

I'm speculating when I think that the DMD chip might just be symptomatic of the problem, and not the cause. It's as if when everything works the chip is running and producing a perfect picture, but when the set 'fails' it's just sitting there getting no instructions and the light passes through the light engine unaltered. I'm wondering if it makes sense that the light emitted in this failure mode should be white, considering it's passing through the color wheel? I also wonder about losing both video, menu AND sound when the picture previously froze - what does this say?

I assume the DVI cable sends the video signal to the dlp board. What if the digital input board simply stopped its output through the DVI cable? Would I see these symptoms? Is it possible to send an external signal through the DVI cable to the DMD board, say from a computer, to test this theory?

I regret to say this is all I have - a whole bunch of questions! I really hope to get some feedback as I'm now at a complete dead-end trying to determine whether it's the DMD or input boards at fault.

[Angel]

If the problem was due to a board failure it wouldn't be another than the DMD. When the analog or digital board fail the DMD board should let you at least to display the TV menu and I think the TV wouldn't turn off.

The light could be white if the DMD chip wasn't switching the three different types of colors.

[oldtech]

Hi Windstar,

Sympathize with your situation. Made a lot of unneeded parts replaced before I found the ultimate cause--color wheel. A group grope is not the way to go. Even though my color wheel was intact and spinning freely it was the culprit.

I recommend that you go to www.samsungparts.com an order the service manual for your set. In it you'll find flow diagrams, troubleshooting tips, and valuable information you can use to isolate your problem. My manual cost me $28.00, whereas replacing a working DLP lamp alone cost me $139.00. Not good economics.

You mentioned one interesting find thus far--a non-working fan. The fact that your set powers up for a short period of time then shuts down sounds like an overheat condtion, which should trigger a shut down. Needless to say all fans and color wheel should be spinning and noiseless.
Placing a fan to the rear of the set may not be enough to provide cooling at the part location where it's needed. You can obtain the fan from the store referred to above for a lot less expense than replacing boards at a $100>. Personally I would begin there.

Hope this helps.

[windstar]

Thanks to everyone for their help and advice. Right now I think it's time to cut my losses and junk the set. -sigh-

I fault Samsung for their lack of integrity, re support & parts. Never again, though, promise.