To give you some background, i bought a Samsung HLP4663W DLP set off of craigslist for an absolutely incredible deal. The guy that i bought it from said he had a tech look at it and they diagnosed it as needing a DMD BOARD, not just the chip. So i get the tv and start fiddling around inside of it. The lamp light was flashing on the tv any time it was turned on, so I thought "start with the easy things, and work your way to the tough things." So i ordered a new lamp off of eBay. After installing the new lamp, it still didn't turn on. So I began some more research into what my problem could possibly be. So i decided to test each major component (color wheel, lamp, ballast) one by one. Here's how i did it.
To test the color wheel, I took the color wheel out of the unit by following the instructions in the service manual. I found that the color wheel was "bad", because any time I would try to turn it, it would make a horrid screeching noise. So i took the actual WHEEL out of it's metal housing, and separated the two parts of the wheel, that is, the actual clear colored "wheel" part, and the "motor" part. It took some force to get them apart, because they are held together by an airtight vacuum. However, upon inspection, there is actually no motor that spins the wheel. It is performed by what i assume is an electromagnet. Therefore the wheel spins without any real connection to its "motor". So i separated the pieces, and then lubed it up with some WD40. It then spun freely without screeching. Then i re-assembled the pieces and took the brown ribbon cable, this is the cable with 4 contacts on it, and taped it down to my workbench, with the contacts facing up. I then took a AAA battery and attached some leads to the positive and the negative side. Then, i attached the leads to the contacts on the ribbon cable, i am not sure which contacts, but i remember it working with a few different combinations. Then, to my amazement, the wheel started twitching! if i tapped the leads repeatedly onto the contacts, it would even spin! This led me to believe that my color wheel was now fixed, and not bad. I then re-installed the wheel into its housing, and re-installed it into my unit.
I then set out to see if my lamp or ballast was bad. To do this it took quite a long time of fidgeting and poking and prodding. What i discovered was this.
If i bridged a certain connection on the DMD, the lamp would fire up! This connection was the two leftmost pins on the connector that went from the DMD to the ballast. I bridged them with a piece of solder. Then, when i went to turn the tv on, VOILA! The lamp came on! This told me that both my lamp and my ballast were fine. The color wheel still did not spin, but due to my previous diagnosis, i still knew it was good.
So what does all of this tell me? That the previous diagnosis of the DMD board was correct. The board is not allowing the color wheel to spin up, firing the lamp, or engaging the DMD chip.
Hopefully this can help some of you narrow your problems down! Because as far as i have seen, this is one of the only ways i have found to be sure if certain components are bad!
Thanks for reading.
There is a good description of the whole process somewhere on the web - I don't remember off hand, but it goes into what has to happen and when.
Color wheel can spin and still not light the ballast - it has to be the correct rpm and this is read by the color wheel board.
Any ideas on where to get a service manual? I've googled but so far nada.
The ballast will usually click when starting up. You should have 320 volts at the ballast input. Make sure the big capacitor on the ballast isn't bulging.
Do you have any missing segments in the color wheel?
If the DMD senses the wheel not spinning fast enough it may never give the 5 volts to the ballast to fire.
If I were to guess I would say you have a bad DMD.
The most common problem with colors wheels is they shatter into a million pieces or a segment breaks off usually causing a loud whirling noise. I suppose your bearings may be bad in the color wheel but not as likely.
I replaced the ballast, did not solve the problem.
So, I removed the color wheel to look at it, without removing any of the conections, and it appeared fine, there were no broken parts.
But, out of curiousity, checking to see if it was some kind of a sensor problem, I turned on the set without placing the wheel back inside its compartment between the lamp and the lens.
The TV ran fine with a black and white picture for over an hour without shutting off.
However, the lamp was getting so hot--I could see smoke flowing about the bright light and also smelled plastic burning, so I turned the set off quickly.
I placed the color wheel back inside its compartment and tried it again.
Again, I got a color picture, and within thirty seconds, the lamp turned off, followed by the sound.
I removed the wheel once more, and the set stayed on as before with just a black and white picture.
I repeated this several times, and each time I got the same results, works fine as long as I did not place the wheel back inside its comparment.
I tried moving the wheel assmbly about to see if the position of the wheel had anything to do with it, but that fail to turn the set off.
Since it works fine without the wheel inside the compartment, I have to assume all the other boards are working fine.
However, I am not certain or confident as to whether it is a wheel problem or not, prehaps it has something to do with the color circuit.
I am also not even certain why the lamp overheats without the wheel attach to its compartment.
I have the servce manual, looked it over, but it is really not that all informative as far as symtoms and repairs go, just the basic stuff.
Any ideas I can follow up on?
HELP! I don't wanna buy the wrong part and perform the wrong repair.
THANK YOU IN ADVANCE!
Hi have the same DLP TV and when i hit the start button no color wheel no lamp comes on so i traced the main power line witch ran from the wall to a small board that has a fuse on its good from there it went into a power board at a 120 volts but there was no power coming out of the line that leads to the ballast. dos this mean that the power board is bad. haven't tryed ur test method yet put i will.
I have one Samsung HLP5085W, with the same problem:
No picture but sound works.
I replaced the bulb and still does not work. I checked all the connections: color wheel, ballast and switch door and everything looks great except that there is a crack in the square glass cover in front of the color wheel. I just want to know, which is the wrong piece the ballast (I measured the voltage and the result it's about 320 volts) or the color wheel?
Note. I followed the procedure you suggested (1] Fans Start 2] Tone Up 3] Color Wheel Starts 4] Lamp Lights 5] You get picture and sound) And I do not hear the Color Wheel spinning up, if the color wheel does not spin the ballast does not fire? I manually checked the color wheel and it freely spins, all the crystals are in good shape.
I really appreciate any help to buy the correct piece.
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