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Backlight problems with my Samsung 2493HM

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Old 15-05-2011, 02:28 AM   #1
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Backlight problems with my Samsung 2493HM

Has anyone heard of similar problems with LCD monitors? The backlight of my Samsung 2493HM has been giving me issues. Often, it will take minutes before it comes on when I turn on my monitor. Sometimes the backlight goes off for a few seconds to a few minutes before coming back. Othertimes it will flicker for a few seconds.

I believe my monitor is out of warranty. Anyone knows if this problem is reparable and where is a reputable place that will repair (preferably house visit as I'm often busy)

Thanks
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Old 15-05-2011, 09:19 AM   #2
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Hi,

Just some questions which came across to my mind..
1) During it takes a minute to turn on, is the Power led on (steady) during that time?
2) If yes, can you see your wallpaper using a flashlight when you shine on the black screen?
If both answers are yes, the logic board is working. So it is likely to be repairable.

From the way you describe it, & if my guess is correct, it is likely to be a fault (capacitor) on the Power board or the inverter board. If my guess is wrong, it could be even the CCFL backlight, but from my experiences repairing these samsungs LCD monitor & TV, so far (touch wood), I have yet to encounter with one.
Btw, how old is it?
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Old 15-05-2011, 02:14 PM   #3
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Yes, and yes.
Reading around, it does look like the caps is the most likely problem.
Slightly past 3 years old :/
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Old 16-05-2011, 06:55 PM   #4
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So do you have the tools to DIY (i.e replaced the capacitors)?

As posted before, i am not a certified repairman. I do this as a hobby. If you trust me, as some others did, i can help. But unfortunately i don't do house call.. I will need to bring back your monitor home. I will PM you my number & we can go on from there,... if you are interested la..
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Old 13-07-2012, 11:54 PM   #5
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PAGING BEARUSDAMHU!!!

Reviving this old thread instead of creating a new one as i have a samsung 2494hs and its gone down and its a similar issue. Symptoms are when u power on, its on for 3 seconds and then off.
You guided me once before on fixing caps on my previous LG monitor with great success. I replaced caps for this Samsung monitor but problem still prevails.

So after digging throught i found this thread and now i think its the inverter which is the problem. Additionally, i tried to shine a torch light on screen, and i can see my desktop.

Need advice on how to proceed, if i need to change the inverter, where to get and how?
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Old 14-07-2012, 01:29 AM   #6
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Hi,

could be a lot of factors.. CCFL, shorted transistor in inverter portion of the power board, capacitors, shorted inverter transformer.. not in particular order..

does your power supply look like this?.. If yes, what is the number on the inverter transformer (the black rectangular component near the CCFL socket)?

If you have multimeter, measure the resistance of the secondary pins of it WITH POWER UNPLUGGED!!.. if not sure where, take pix then i show u where to measure.. I am suspecting that component is faulty..

BTW, what brand and series capacitors did u replaced it with?..
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Old 14-07-2012, 01:48 AM   #7
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YES IT LOOK EXACTLY LIKE THAT! i just bought a multimeter today from SLT but not sure how to test.



The caps i replace with nicyon etc caps. i made sure they are not the lousy ones as per ur advice from last time.
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Old 14-07-2012, 02:16 AM   #8
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The inverter number is TM-10176 TNE 0848 D T.
Which are the secondary pins?
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Old 14-07-2012, 04:27 PM   #9
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Upz for bear.
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Old 14-07-2012, 05:27 PM   #10
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Sorry was v v v busy.. part time repairman,, Full time Father and husband here.. There are mouths need to be fed, house need to be cleaned and wife need to be satisfied..

nicyon??!.. hmm.. never heard before. how do u know they are not lousy? some monitors are 'picky' of the capacitors that you replaced. So please match the original Ripple & ESR spec with the original ones..

Anyway,.. behind the inverter transformer there are 2 pair of pins (total 4 pins) closer to the CCFL connector.. With power UNPLUGGED, measure the resistance of pair A vs pair B.. If it is more than 3% resistance difference, then it should be replaced .. Set your multimeter to 2k ohm range.. it should be around 900-1100 ohms.

Good luck..
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Old 14-07-2012, 08:33 PM   #11
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thanks man. Yeah this monitor im repairing also for a relative haha.. also a busy man. Kena hired n pressured to try to fix this haha.

Okay going to try to test teh capacitance. One thing not sure though, where do the black and red leads go? any particular order? And mainly, where would i purchase the inverter cos tahts my main concern. I dont mind changing capacitors again if needed, but kinda wondering where to find the inverter i need and the type.
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Old 14-07-2012, 09:10 PM   #12
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Okay going to try to test teh capacitance. One thing not sure though, where do the black and red leads go? any particular order? And mainly, where would i purchase the inverter cos tahts my main concern. I dont mind changing capacitors again if needed, but kinda wondering where to find the inverter i need and the type.
Not capacitance but resistance. For resistance of the inverter transformer the probe doesnot matter. The inverter transformer are usually available online from ebay or taobao.
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Old 14-07-2012, 09:50 PM   #13
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okay one pair reads around 1080ohms...the other pair prooves to have a hard time to get any readings. if i do sometimes it flashing 1500, sometimes 1800, sometimes 1300. Around these regions, nothing stable enough because they dissapear after 1 second.

Can direct me to where would i purchase my inverter. does it have to be the same number as you asked me, or can it be any kind?
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Old 14-07-2012, 09:56 PM   #14
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wow! update : measured under the 20k ohm range instead. one pair shows 1.08 which equates to 1080 as above. But the other pair that i had hard time reading, shows 10.60 consistantly which equates to 10600ohms.

I dont know what to make of it, but it seems large.
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Old 14-07-2012, 11:47 PM   #15
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wow! update : measured under the 20k ohm range instead. one pair shows 1.08 which equates to 1080 as above. But the other pair that i had hard time reading, shows 10.60 consistantly which equates to 10600ohms.

I dont know what to make of it, but it seems large.
By the reading u mentioned, it is faulty. desolder it and confirm measurement again.
If still same, replace it with the same model.. go taobao and search.. btw.. it is advisable to replace the capacitors to better known series.. my favourite is panasonic fm, fk, fc series..
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