Samsung syncmaster 2493hm doesn't work

[RichiDev]

Hello,

i have a bad Samsung SyncMaster 2493hm and i don't know how to fix it. I read many threads on this forum about this monitor but i still didn't got the monitor to work.
When i switch the monitor on with power switch, nothing happens. The blue power LED don't light and pressing buttons on front panel makes nothing.
The monitor has bn44-00195a power board. When i disassemble the monitor and connect the power board with the logic board and switch on the power switch i can measure 5.2V standby signal S_B and 0V PS_ON signal on connector CN851.
On the logic board on connector CN702 (for flat cable to front panel power LED and buttons) i can measure:

pin 1 = 0V
pin 2 = 3.3V
pin 3 = 3.3V
pin 4 = 0V
pin 5 = 3.3V

But when i connect the flat cable to the connector CN702 then voltage on pin 3 drops to only 1V and the blue power LED don't light. So that i can't start the power supply with ON/OFF button on front panel.
But if i short PS_ON with B_E when logic board is disconnected the power supply starts working. I can measure 24V, 5.4V. So i think the power supply is OK, but there is something wrong with the logic board. But i don't know what.

The blue LED is OK, i tested it with multimeter through the flat cable.

Do you have any ideas what to test or measure or something?

thank you very much
Richi

[R_J]

Re: Samsung syncmaster 2493hm doesn't work

CN702 Pin1 is ground, Pin 5 is +3.3v, Pin 4 is LED, Pin2 is Key2 and Pin 3 is Key1, so you could have a bad keypad button on the Key1 line. Check the p-touch function board

[RichiDev]

Re: Samsung syncmaster 2493hm doesn't work

Hi,
thanks for your suggestion. It looks like really something bad on the small front panel PCB. Probably the ADA04 IC.

thank you