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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
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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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Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956

Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999

Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

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TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
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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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Old 04-26-2018, 12:08 PM   #6
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Lightbulb Re: Syncmaster 2493hm : no power no blue led, need help

Please mention board number(s) (possibly something like BN44...). The same power board (and other boards) can be found in other Samsung models too.

If I remember right, 2493HM and 245B have same power boards, either BN44-00173A or BN44-00195A. The very well known fix for BN44-00173A is to replace 3 resistors and some electrolytic capacitors (can be found in older posts in this forum). BN44-00195A is usually much harder to fix, easiest way is to use BN44-00173A instead (they are compatible). Some tips for it however is also available in older posts.

Last edited by euromatlox; 04-26-2018 at 12:21 PM..
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Old 04-27-2018, 10:04 AM   #7
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Default Re: Syncmaster 2493hm : no power no blue led, need help

Quote:
Originally Posted by disorder View Post
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.

I have one too that i picked up on the curve some time ago and also power up with blue led and no pic,i fixed,check post #76

check this thread,there is a lot info. https://www.badcaps.net/forum/showthread.php?t=14483

Last edited by ivtec; 04-27-2018 at 10:19 AM..
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Old 04-28-2018, 08:47 AM   #8
disorder
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Default Re: Syncmaster 2493hm : no power no blue led, need help

hello, thank you guys, i will check that.
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Old 04-28-2018, 09:06 AM   #9
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Default Re: Syncmaster 2493hm : no power no blue led, need help

my board is BN44-00195A , i have test some more points and find that :

i have soldered a 800ohm resistor between SB and power-en :
when i don't plug the cn600 ribbon cable i have nothingon logic board and power board is noisy

when i plug cn600 only i have 3.3v , 1.2v and +5vmicom line only , not other lines. the power board is not noisy

if i unplugged only sb and power-en from cn600 and left 5v plug, il have +5v but not +5vmicom, 1.2 and 3.3v lines.

thank you for help
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Old 04-28-2018, 09:25 AM   #10
ivtec
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Default Re: Syncmaster 2493hm : no power no blue led, need help

Quote:
Originally Posted by disorder View Post
my board is BN44-00195A , i have test some more points and find that :

i have soldered a 800ohm resistor between SB and power-en :
when i don't plug the cn600 ribbon cable i have nothingon logic board and power board is noisy

when i plug cn600 only i have 3.3v , 1.2v and +5vmicom line only , not other lines. the power board is not noisy

if i unplugged only sb and power-en from cn600 and left 5v plug, il have +5v but not +5vmicom, 1.2 and 3.3v lines.

thank you for help
Disorder did you re-solder all solder points in the power Supply?,did you clean all that glue around components that dried and cause conduction between legs ? did you take out scraped legs on 47pF 1KV capacitor (CM809 on the schematics and resolver it back? did you follow the whole thread that i posted ,where there is many tips to fix this monitor?,
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Old 04-28-2018, 09:54 AM   #11
disorder
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Default Re: Syncmaster 2493hm : no power no blue led, need help

hi,

the glue is really hard to remove but yes i have cleaned that.

the solder joints look good but ok i will do that

i did't try 47pF 1 KV capacitor to resolder , i'll do

but my problem is not like yours, the blue led not shine, it's like the display is dead

thank you
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Old 04-28-2018, 12:39 PM   #12
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Default Re: Syncmaster 2493hm : no power no blue led, need help

I have once fixed BN44-00195A, what I did was to replace SI-8008HFE DC voltage regulator and then also some SMD components following these Toasty's tips:

https://www.badcaps.net/forum/showth...t=18966&page=2

I also replaced some electrolytic caps (near that Sanken 8008HFE).

However the fix worked only a day or two. I decided to change the whole board using BN44-00173A instead. After that no problems.
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