I have a Sanyo DP42848 LCD tv that has no backlighting. Actually the screen is lit for about half a second each time the unit is turned on. Using a flashlight I determined that the display is functional, also the 24vdc power supply is up and stable. With the slave inverter unplugged I have backlight on the right side for about 2 seconds. I even tried running the inverters with a separate 24vdc supply, no change. Now I just replaced both inverters with new ones, again no change. Any ideas as to where I should go from here? Thanks for your help.
Model: DP42848 lcd
Hi. I'm Steve. I'm sorry to hear about your TV. I will try my best to give you a precise and accurate answer.
I'm not over-familiar with Sanyo LCDs but I will tell you that the most likely problem is the loss of one of the CCFL lamps that provide the backlight. Typically there is a balancer circuit that works with the two inverters. When it detects a mismatch in load (when a lamp fails), it will signal the power supply to shut down the inverters.
You say that the screen is lit for a second or two...in a darkened room, see if you can determine where the failed lamp is located around the perimeter of the screen.
Then, you have to decide whether or not to try and change out the lamp. This is the domain of the very brave but it can be done and the lamps are readily available: http://www.ccflwarehouse.com/
It is also possible that you will destroy your panel. Personally, I have never done one of these swaps.
I'll be here if you need more help. I want you to be 100% satisfied with my answer.
Please bookmark my web page at www.stevetheguru.com so that you can contact me with your future electronic questions.
Thanks very much.
VP of electronic repair company. Audio nut.
Hey Steve,Thanks for the reply. How many lamps are there in a typical lcd tv? I'll probably attempt to change them since the set is useless as is. At least there is some chance I can get it working again. By the way, please check to see if you received your payment. I accepted your answer but then when I tried to leave feedback my browser force closed before I got done, now the available options are different. This may have been caused by lightning and heavy rain in the area just as we were conversing. Let me know. Thanks again!Doug
I did receive payment. Thanks very much.
As I indicated previously, I'm not familiar with the Sanyo unit you have there but a typical length is 2" (50mm). So divide the perimeter of the panel by 2" and that will be in the ballpark.
Again, the way to see which one is out, is to dim the room and keep turning the TV on and off and try to see where around the edge has a dark space. That's the bad lamp.
Get the size and go to www.ccflwholesale.com