EagleTG
Active member
Working on a 52" DLP screen that's in a House of the Dead 4 cabinet. It is model number 52SX4D or 52SX4DUB.
It started with no image on the screen. I was getting a continuously blinking red light on the front of the unit (NOT the Lamp light, the standby light).
I took it apart, found that the power supply board had a few bad capacitors (via completely testing the board caps with an ESR meter). I've replaced those and done some other basic testing on the power supply (diodes, transistors, resistors, etc. all look good) now am getting a 5-blink code from the standby light. According to the service manual, this is normal standby mode. Yet I've got an input signal. I've also noticed that the fans do not stay running on the unit. The bulb never fires, yet I'm relatively certain the bulb is good. The TV is not showing any indications of lightbulb error codes, and the bulb is visually perfect (although I know this is not always the best way to test these bulbs).
I've tested the output of the ballast with an HV Probe, I get nothing from it. I'm assuming that it's due to other parts of the start-up not completing properly. I've read that there is a chain reaction start-up that occurs on these units, and if anything doesn't go right, it will terminate the boot process.
I was able to get the unit booting further, not quite sure how or why. In this case, the unit would show a solid red standby light and briefly blink the lamp light green. Then it would restart with the red standby light. The bulb still never fired in this mode. I was only able to get it to boot this far during one of my testing sessions.
As of now, I'm back to the solid red standby followed by 5 red blinks of this light. The process then restarts. The fans are back to running for about 3 seconds on initial boot before they stop. This REALLY looks like a power supply issue to me, but I can't seem to find it.
I had initially purchased another ballast, but have not installed it to try yet. I'm assuming it's not the problem at this point. I can't quite reach the 5V Lamp Enable plug to test it while in-operation (also, I'm not quite sure what the pin-out should read on this, as I can't seem to find that information in the service manual... even if I could reach either end of this plug).
I've tested the outputs of the power supply board and everything looks generally in-spec. I'm going to go through the outputs in more detail and will post the results now that I have the service manual (I was going by what was printed on the board).
I've done so much work and diagnostic on this thing, I'm sure I'm missing some info in this post.
I thought I'd post here and see if anyone had any better ideas. I will try over on FixYourDLP.com soon. I've also extensively Googled for information on DLP startup processes, and other common issues with this model and others. I've read a ton of information, but am open to suggestions on other things to try.
Thanks all!
Edit: I've also read that the color wheel needs to spin up before the bulb will fire. I've confirmed that the wheel is not seized, broken, or otherwise damaged. It does not spin during any of the boot process... however I've only been able to test that during the "3 second fan burst" boots.
It started with no image on the screen. I was getting a continuously blinking red light on the front of the unit (NOT the Lamp light, the standby light).
I took it apart, found that the power supply board had a few bad capacitors (via completely testing the board caps with an ESR meter). I've replaced those and done some other basic testing on the power supply (diodes, transistors, resistors, etc. all look good) now am getting a 5-blink code from the standby light. According to the service manual, this is normal standby mode. Yet I've got an input signal. I've also noticed that the fans do not stay running on the unit. The bulb never fires, yet I'm relatively certain the bulb is good. The TV is not showing any indications of lightbulb error codes, and the bulb is visually perfect (although I know this is not always the best way to test these bulbs).
I've tested the output of the ballast with an HV Probe, I get nothing from it. I'm assuming that it's due to other parts of the start-up not completing properly. I've read that there is a chain reaction start-up that occurs on these units, and if anything doesn't go right, it will terminate the boot process.
I was able to get the unit booting further, not quite sure how or why. In this case, the unit would show a solid red standby light and briefly blink the lamp light green. Then it would restart with the red standby light. The bulb still never fired in this mode. I was only able to get it to boot this far during one of my testing sessions.
As of now, I'm back to the solid red standby followed by 5 red blinks of this light. The process then restarts. The fans are back to running for about 3 seconds on initial boot before they stop. This REALLY looks like a power supply issue to me, but I can't seem to find it.
I had initially purchased another ballast, but have not installed it to try yet. I'm assuming it's not the problem at this point. I can't quite reach the 5V Lamp Enable plug to test it while in-operation (also, I'm not quite sure what the pin-out should read on this, as I can't seem to find that information in the service manual... even if I could reach either end of this plug).
I've tested the outputs of the power supply board and everything looks generally in-spec. I'm going to go through the outputs in more detail and will post the results now that I have the service manual (I was going by what was printed on the board).
I've done so much work and diagnostic on this thing, I'm sure I'm missing some info in this post.
I thought I'd post here and see if anyone had any better ideas. I will try over on FixYourDLP.com soon. I've also extensively Googled for information on DLP startup processes, and other common issues with this model and others. I've read a ton of information, but am open to suggestions on other things to try.
Thanks all!
Edit: I've also read that the color wheel needs to spin up before the bulb will fire. I've confirmed that the wheel is not seized, broken, or otherwise damaged. It does not spin during any of the boot process... however I've only been able to test that during the "3 second fan burst" boots.
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