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Old 04-16-2018, 06:22 AM   #1
disorder
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Default Syncmaster 2493hm : no power no blue led, need help

hello all,

it's my first thred on this forum, but i read it for a long time.
i have troubleshooting with a samsung syncmaster 2493hm dysplay

it doesn't start, sources plugged or not, and there is no blue led !

fuses are ok, caps are looking good and values are ok on de smps with the multimeter (Farad test)
+5v wicom is ok
but +5v, power_en and +5v panel are not present

on the mainboard , i have 3.3V_live and 1.8v_live ok

r391 : no voltage

i found for ic304 something strange but values are ok :
-r388 : +5v on one side and only +0.07V on other side
-but the resistance value is 2.2kohm with multimeter

i found it very low for ic300 , don't you think ?

if someone can help me what i have to control now .

thank you a lot.
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Old 04-16-2018, 01:26 PM   #2
budm
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Default Re: Syncmaster 2493hm : no power no blue led, need help

Can you please upload good clear pictures so we can see what we are dealing with?
"i found for ic304 something strange but values are ok :
-r388 : +5v on one side and only +0.07V on other side
-but the resistance value is 2.2kohm with multimeter"

What is the resistance reading witH ref to GND on that end of the resistor that shows +0.07V?
Is that end of the resistor connected to IC304? Pin number?
IC304 P/N?
As you can see, we do not have much of the details to go by.
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Old 04-16-2018, 03:42 PM   #3
disorder
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Default Re: Syncmaster 2493hm : no power no blue led, need help

hello, thank you, i'll post some pictures tomorrow.

for ic304 and r388 i have 5v on pin 1 of ic304, and i have 0.07v at pin3, also between r388 and c302

i have also try to force start of smps by putting a 800ohm resistor between SB and power_en : i have 24v now but no screen and no blue led .

i think motherboard is dead, not smps.

thank you
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Old 04-16-2018, 09:34 PM   #4
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Default Re: Syncmaster 2493hm : no power no blue led, need help

Service manual:
https://www.manualslib.com/manual/11...ng-2493hm.html
There Voltage regulator ICs on the main board that you should check the Voltages.
What is the history of this monitor?
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Old 04-17-2018, 03:27 PM   #5
disorder
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Default Re: Syncmaster 2493hm : no power no blue led, need help

i have no clear history : before the display could power on only after 2 or 3 days plugged in. blue led was ok.
and one day : nothing.
i have not more informations.

thank you for the complete schematics, i had not the voltages on lines, i will check that and come back.

thank you very very much for help
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