Samsung Odyssey G9 (c49g95tssr) no picture or backlight. Power LED shows

[grimreaper]

hey guys,

i bought 2 samsung odyssey g9's for a decent price. they both have the exact same fault. when plugged into a power source, the blue led powerlight shows, but when turned on there is no picture, no backlight, no menu, nothing. when plugged into a laptop the laptop recognises the monitor, but keeps disconnecting and reconnecting.

The power supply connects to the main board. There is like a checkpoint on the mainboard that says 20v, and i tested that with a multimeter and i can confirm that I'm getting 20v in. There are a few ribbon cables coming off from the mainboard to the T-CON. I tested those voltages, and those are really low. Less than 1v.

I attached a picture of the main board.

1 - 20v power cable directly from PSU
2 - ribbon cable going to TCON - LOOKS LIKE CORRECT VOLTAGE IS OUTPUT
3 - another ribbon cable going to TCON - DOESNT LOOK LIKE CORRECT VOLTAGE IS OUTPUT (<1V)
4 - cable leading to power button and LED backlight (BACKLIGHT DOES NOT WORK, BUT POWER LED DOES) (DOESNT LOOK LIKE CORRET VOLTAGE IS OUTPUT (<1V))
5 & 6 - labelled LED, not exactly sure where this goes

dont have any schematics or diagrams unfortunately. any ideas?

thanks

[indeterminate]

Start with the power supply
it sounds like the standby supply is working but the main power supply is not starting up.
be careful there will be 400v on the board for a long time after it is disconnected from mains.

[grimreaper]

The power supply connects to the main board. There is like a checkpoint on the mainboard that says 20v, and i tested that with a multimeter and i can confirm that I'm getting 20v in. There are a few ribbon cables coming off from the mainboard to the T-CON. I tested those voltages, and those are really low. Less than 1v.

I attached a photo and a bit more information in my original post. from my beginner knowledge of electronics ( ) after testing the power supply, i think its fine. 

[jzx]

Check if you have 20 V when the monitor tries to start (connected to a pc). Sometimes the power supply can give the voltage unloaded, but not loaded, then the main circuit goes off again and the cycle repeats. The power suply cannot give enough current, often due to bad electrolytic capacitors.