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Louie, Technician
Category: TV
Satisfied Customers: 2557
Experience:  25+ yrs. experience in the field and 5+ yrs. online, down to component level.
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I have a Samsung HTL5075sx dlp tv in which I thought needed

Customer Question

I have a Samsung HTL5075sx dlp tv in which I thought needed a new DMD board. However after replacing the lamp which works, the ballast, and the DMD board the the lamp will not light unless I bridge a connection on the plug that goes from the DMD board to the ballast. The color wheel spins up to the rpm it is supposed to so now I have no idea what else to diagnose. The only light on the front that is active is the Lamp light that blinks green for about 45 sec and then repeats the process.
Submitted: 7 months ago.
Category: TV
Customer: replied 7 months ago.
However, I just discovered that when the kill switch is on I receive the 5v pulse I am supposed to be getting to the ballast but when I flip the switch to turn it off is when I don't get a reading or a reading up to 1v and the lamp lights for a couple of seconds
Customer: replied 7 months ago.
Could this mean a faulty kill switch?
Expert:  TV Tech1 replied 7 months ago.

Are you talking about the blue paddle switch behind the lamp door? That has to be jumpered to get the light to light up.

Customer: replied 7 months ago.
Kind of, there's a circuit board on the lamp ballast that's connected to the DMD board. On the pins that are on the connector attached to the ballast board I try and test the pulse and it bridges a connection is my guess and it lights the ballast for a couple of seconds
Expert:  TV Tech1 replied 7 months ago.

That's the small connector on the ballast I believe. There's a 5 Volt line, ground, ballast strike/run line that when you ground it causes the lamp to go to strike mode, and then a line that verifies if the lamp lit. You're probably activating the strike/run line by grounding it. But there is no kill switch attached to that part, only the door switch could be considered a kill switch. If the blue paddle switch isn't held down constantly the ballast won't fire at all. And the color wheel must get up to full speed before the DMD will even activate the ballast circuitry. Maybe you should take a picture and use our paperclip button to post it on our site here. Use your photo editing software to circle the kill switch you're talking about.

Customer: replied 7 months ago.
I am referring to the lamp door switch
Expert:  TV Tech1 replied 7 months ago.

Look at your picture here. Do that and listen to your color wheel, it should spin up to a CONSTANT speed, no variation. THEN the lamp crackles or makes a "Blink" sound if it strikes properly. THEN the lamp should stay lit OR it goes out and the ballast attempts to strike it 2 more times before it gives up and shuts down. Tell me what you experience, ok?