Electrical Arc at power input - Samsung CRT
 

Hi All,

I'm currently working my way through a TV repair, and having some trouble with an unexpected issue.

1) The TV was brought in with a complaint that the green color was not displaying on the tube.# I turned the TV on before starting repair work and verified that no green color appeared.# Red and blue operated as expected.

2) I opened the TV and pulled the PCB out of its slot.# At this point, I had not made any alterations or conducted any repairs or diagnostics.# I then turned the TV on with the tube / neck / board exposed to observe operation.

3) When turning the TV on while open, I noticed that there was electrical arcing underneath the board between the positive / negative power terminal and ground connection.# This is where the molex with power from the wall socket plugs into the board.##

While the TV initially seemed to power up before opening it, after opening it (before any work) the TV would not power up properly.# The electrical arc at power caused the green "on" LED to flicker and the unit was clearly not receiving power correctly.

4) Initially I suspected some kind of cold solder joint, so I reflowed solder to these connections on the board.# No dice.# Same issue.#

Interestingly, while diagnosing the issue, I accidentally powered the TV on without the anode cup connected to the tube.# The crackling alerted me as to my grave error.# That said, I noticed when the anode cup was not connected I heard the TV "bootup" noise that I was not hearing earlier.##

The TV model is a Samsung TXL2091F from September 2001.# I have not been able to locate the service manual / schematic for the unit.# I repair arcade monitors often and know my way around CRT repair, but this one has me stumped.

Any feedback would be appreciated.# The fact that the board made a boot noise when the anode wasn't connected may be a clue, but I don't know what.

I have attached images of the PCB and area where the arc is occurring.


Thank you for any help or insight!

Dave

1) fuse socket loose
2) 3 legged degauss resistor if used. Usually marked TDK.
3) on/off relay or pins.
4) AC input choke or pins
5) other things I dont remember !!

If not obvious darken the room & tap around & bend the PCB to get it
to act up. When it does you should see it.
Good luck
73 Zeno:smoke:
LFOD !