SAMSUNG PN43E450A1F Won't Turn On

[1beertap]

Hey guys, I am working on this plasma tv for a coworker. The unit will not turn on and there is no indicator lights around front of bezel. I have tested voltages on power supply to as follows:

PS-ON 2.43V
STBY 5.26V
GND 0V
D15V 0V
GND 0V
GND 0V
D5.3V 0.03V
D5.3V 0.03V
GND 0V
D15V 0V
D15V 0V
D5.3V 0.03V

Any ideas? Thanks.

[tech2014]

Re: SAMSUNG PN43E450A1F Won't Turn On

Have you tried removing the connector from the the Y SUS and Z SUS one at a time to see if you get voltage.Measure the resistance on the VS and VA lines. There may be a short on the Y or Z sustain boards, or a shorted buffer board.

[1beertap]

Re: SAMSUNG PN43E450A1F Won't Turn On

tech2014,

I tried removing both Y SUS and Z SUS one at a time and there is no change in voltage. Also, there are no clicks from the relays. I'm not sure what resistance that you want me to check on the VS and VA lines. In other words, where do I need to connect my test leads in order to check VS and VA resistance? I do see the VS and VA test points on the power supply.

[1beertap]

Re: SAMSUNG PN43E450A1F Won't Turn On

I grounded the PS-ON and all voltages came up including VS and VA, but I did not hear the relays click and of course no picture.

[tom66]

Re: SAMSUNG PN43E450A1F Won't Turn On

This board does not use relays so you won't hear anything click. (This is rare with plasma TVs. Relays are almost always used on the PSU but Samsung decided to omit them and just use simple NTC devices.)

[sordids999]

Re: SAMSUNG PN43E450A1F Won't Turn On

or a shorted buffer board.

https://www.youtube.com/watch?v=51SZsfH60EY

how to test your buffers for shorts

[1beertap]

Re: SAMSUNG PN43E450A1F Won't Turn On

sordids999,

I tested for shorts as per video, buffers test good no shorts. thanks.

tom66,

thanks for pointing that out.

[Hamie]

Re: SAMSUNG PN43E450A1F Won't Turn On

common failure in this set is a faulty z-sus.
Igbts shorted on the underside of the board.

Have you tried running test patterns?

[1beertap]

Re: SAMSUNG PN43E450A1F Won't Turn On

Hamie,
i found no shorts on any of the igbts located under the z-sus or y-sus boards. I not sure how to run a test pattern with no picture. thanks for the info.

[Hamie]

Re: SAMSUNG PN43E450A1F Won't Turn On



Ok jump holes 3 and 4 on the control board.

Put back in your jumper on the power supply between ps-on and gnd.

Remove the lvds cable that connects the main av board to the control board.

Plug in the tv

[1beertap]

Re: SAMSUNG PN43E450A1F Won't Turn On

Hamie,
The panel comes on with test patterns showing changing colors but i notice a horizontal black bar in the middle of the screen.

[1beertap]

Re: SAMSUNG PN43E450A1F Won't Turn On

I found out why I had a bar in the middle, one of the tab bonds wasn't plugged in all the way. Sorry for the confusion. The screen shows up great now.

[tom66]

Re: SAMSUNG PN43E450A1F Won't Turn On

Good, was about to suggest that, or the panel might have a small crack on the edge (these newer PDPs will still display an image in some cases), but all sorted now.
This would indicate the main board is bad then.

[1beertap]

Re: SAMSUNG PN43E450A1F Won't Turn On

tom66,
This was my thinking also. Thanks. I'll post back when I have a replacement installed.