Samsung 42" plasma fault

[the79bomb]

I have model pn42a400c2dxza

It comes on for just over a second and the relay cuts off power (Still have 5v on standby pin). For that 1 second the screen looks off (see screenshot)

Unplugging the power cable to all of the boards has no effect except when unplugging the board with a/v inputs (main board) in which case it does not turn on at all.

It appears there is an overload somewhere. The cable from the central board to the board with the a/v inputs (main board) was damaged when I got the unit so some of the pins might have shorted. I have repaired the cable but this has not resolved the issue. It might be that there was originally 1 thing wrong with the tv (off picture) but while messing around someone damaged the aforementioned cable and caused the 2nd problem (power overload).

Would anyone be able to instruct me how to diagnose for sure which components need replacing?

thanks for any help.

[tom66]

Re: Samsung 42" plasma fault

Looks like a power connector isn't plugged in.

Failing that... unplug X-main, does problem remain? Then plug X-main back in and unplug Y-main? Does problem remain?

[the79bomb]

Re: Samsung 42" plasma fault

Thanks for the reply. I have tried unplugging each board. both x & y mains as well and the problem remains. the only change is when I unplug the main board and then nothing happens. I just hate to pay for a main board and have that not be the problem or not be the only problem. That is why I wanted to be sure.
Thanks, Tim

[tom66]

Re: Samsung 42" plasma fault

Thanks for the reply. I have tried unplugging each board. both x & y mains as well and the problem remains. the only change is when I unplug the main board and then nothing happens. I just hate to pay for a main board and have that not be the problem or not be the only problem. That is why I wanted to be sure.
Thanks, Tim

Can you post a close up picture of the power connector going from the power supply to the logic card?

[the79bomb]

Re: Samsung 42" plasma fault

Thanks for the response. I have attached a better picture of the connector to the main logic board from the power supply as well as a clearer picture of the overall system with enough res to zoom in. I have tried starting the system with virtually every combination of power cables plugged in/unplugged with no change - system clicks off after 1 second unless the main board is unplugged in which case nothing.
Thanks, Tim

[tom66]

Re: Samsung 42" plasma fault

Can you post a clearer picture so I can read the legends on those connectors?

[the79bomb]

Re: Samsung 42" plasma fault

my camera will not focus closer. no macro mode on my camera for taking close up shots. The codes on the connectors are as follows from left to right:
stby,vs-on,n c,ps-on,rtn,5. 3v, rtn, rtn,5.3v,5.3v

all "5.3v" pins have 5v for the 1 second but then 0 after the relay clicks off. "Stby" has 5v throughout. However ps-on has 0v with relay closed and then 3.3 when it clicks open. This is with the connector unplugged as pictured meaning that something on the main board is causing the relay to open as it is the only board plugged in to the power supply board - see picture.

Thanks, Tim

[tom66]

Re: Samsung 42" plasma fault

5V, or 5.3V? Many of these Samsungs depend on that 0.3V.

[the79bomb]

Re: Samsung 42" plasma fault

I read 5v but now I'll double check it and let you know.

[the79bomb]

Re: Samsung 42" plasma fault

The standby pin has 5 volts and the 5.3 do indeed have 5.3 volts for a second. My volt meter takes a second to get the reading so it was hard to get a stable reading but it is 5.3 volts.

[tom66]

Re: Samsung 42" plasma fault

Okay. Disconnect Y and X sustains as well as their control connectors, then try again. You should get no picture but if it stays on you have a problem with a sustain board.

[the79bomb]

Re: Samsung 42" plasma fault

there is no picture but the power still clicks off after 1 second

[tom66]

Re: Samsung 42" plasma fault

there is no picture but the power still clicks off after 1 second

Do you have a pin-out for the power connector. Is there a pin called PSON or ON/OFF?

[the79bomb]

Re: Samsung 42" plasma fault

There are no pins on the power board. It seems to me that there is some overload in the main board causing power to shut off after 1 second. I was unable to find any jumper pins on the main board either. The main logic has 4 but there is no jumper present but it cannot be the source of the problem as it is unplugged.

[PlainBill]

Re: Samsung 42" plasma fault

There are no pins on the power board. It seems to me that there is some overload in the main board causing power to shut off after 1 second. I was unable to find any jumper pins on the main board either. The main logic has 4 but there is no jumper present but it cannot be the source of the problem as it is unplugged.

Miscommunication. The second picture in your first post shows an over-all view of the TV. A cable runs from a connector in the lower right corner of the power supply to the main board. Frequently the manufacturer will identify the function of each pin of that connector. That information is very useful when troubleshooting.

PlainBill

[the79bomb]

Re: Samsung 42" plasma fault

Thank you for clearing that up. The pins are as follows:
Fan On (0V)- NC
D13v(.3v) - D13v(.3v)
D13v(.3v) - RTN
RTN - RTN
5.3 (0v) - 5.3 (0v)
5.3 (0v) - 5.3 (0v)
RTN - RTN
RTN - RTN
13 VAMP (.3V) - 13 VAMP (.3V)
RTN - RTN
STDBY (5V) - RTN
PSON (4.1V) - NC

[selldoor]

Re: Samsung 42" plasma fault

Do you have a pin-out for the power connector. Is there a pin called PSON or ON/OFF?

Hi- I have located a wiring diagram? for BN44-00206A which I believe is the power board for this tv. It has detail of the connectors.

[selldoor]

Re: Samsung 42" plasma fault

Whoops missed the edit cut off so its a new line sorry.
I have also found a trouble shooting guide which may help at some point.
Though I expect you already have it?

FORGET THAT - Wrong Model though possibly same power supply