Samsung PN51D450A2D - Need help - Full Detail
Hey Guys, Im in need of some direction and assistance.
First off some background on me. I work in the electrical distribution industry, have over 15 years of mobile audio / remote starter installation experience, am firmilliar with electrical and electronics, but not so knowledgeable when it comes to circuit boards and televisions.
I have a Samsung PN51D450A2D Plasma television, a month or so ago it was on working fine, then I left the room and came back a while later to find it off and non responsive.
I pulled the back panel off, checked the fuse – was still good – but it was still un responsive. Came to the conclusion that my Power supply board was toast. Ordered a new one off ebay.
Installed the new power supply board and powered on.
The indicator led on the front of the tv lights up red and the tv plays the “Samsung tune” but no picture. No change in the screen what so ever from powered off state.
The green diagnostic light on the logic board is blinking 5seconds on 2 seconds off. Based on what ive found online this indicates Driving Board Problem (DRV Reset): LED ON for 5 seconds → LED Off for 2 seconds.
When I test the VS Testpoint on the powersupply board I only get 10 vdc. When I test the Va I only get 1vdc.
I removed and visually inspected the x and y boards and they did not look to be damaged /blackened/ or have any bulging or ruptured components.
When I removed the main board (one with the hdmi inputs) it looked like there may have been some corrosion, or oxidation on the board and the back side sticky. I took some isopropanol and attempted to clean off as much as I could. I re installed the board and attempted to turn on the tv. I didn’t get anywhere past where I was stuck.
Thinking I had a damaged board I ordered a new main board.
Installed it and still nothing.
On suggestion of the seller of the main board I replaced the logic board as well.
Still nothing new, same 5 sec on, 2 sec off diagnosis light.
At this point I tried some random trouble shooting.
I removed the xmain from the y main (xmain is fed from ymain)
Removed the y main from the powersupply,
I removed all the boards from the power supply and powered on.
Nothing at all.
Then I attached the mainboard to the power supply.
I added the logic board to the powersupply and now the tv will turn on and playing the Samsung tune and 5 on 2 off blinks.
One by one I removed the various ribbon cables to the logic board. Each time I plugged in the tv I would get the Samsung tune. However, once I removed the ribbon cable from the y main to the logic board the tv went will click 5 times like its attempting to fire up. Then just turn off.
If I connect the ribbon cable to the y main and disconnect the ymain from the power supply board it goes back to playing the Samsung tune and 5 on 2 off blinks.
This lead me to believe I had a faulty y main.
Replaced this and same issue.
It seems that no matter what I do I cannot get a reading higher than 10vdc on my vs testpoint on the powersupply and 1vdc on VA.
I have metered my VSON between my powersupply and logic and have 0vdc all the time regardless of what I do.
I have done a ton of research online but cannot find anyone with a similar issue of low vs/va readings.
If there is something im missing or something I can test to help diagnose the issue please let me know and I will test and report back asap.
I would like to salvage this Television, but im getting close to the point of “office spacing” this tv in a field.