Samsung 2253LW

[selldoor]

Re: Samsung 2253LW

@jahjhai Have you done the resistance test on inverter transformers
and the diode tests on the 8309.
Can you tell us what numbers are on the parts indicated in Bigdaddyady's picture.

[BigDaddyAdy]

Re: Samsung 2253LW

I've done the following thing:
I replaced R241 with a variable resistor and got the monitor working at around 40Kohm.

I would like the exact value of it, so i can replace it with a fixed value.
So, i really need that value please.

[BigDaddyAdy]

Re: Samsung 2253LW

It seems that budm was right, I think all i did was to trick the DET signal for the inverter to start. After the inverter started i noticed that the left half of the screen is darker. Though i checked all the lamps with a notebook inverter, it seems thet one of them has a problem.

[budm]

Re: Samsung 2253LW

Check closely on the wires that are attached to the end of the lamps, tug on it gently to see if it will come off.
It is hard to burn out 40K resistor since there is not voltage high enough on the inverter driver side of the circuit to force enough current to flow through 40k to cause it to burn up.
It is another reason to make two test lamps to locate the problem. Like this thread that we spent so much time on it.
https://www.badcaps.net/forum/showth...410#post410410

Bad lamps:
http://s807.photobucket.com/user/bud...?sort=3&page=1

Test lamps:
http://s807.photobucket.com/user/bud...?sort=3&page=1
https://www.badcaps.net/forum/showthread.php?t=19987

[BigDaddyAdy]

Re: Samsung 2253LW

OK, so it seems there is still a problem with the inverter.
I checked out the lamps and they are ok.
I tested the inverter with another set of lamps and the same problem appears:
The lamps do not fully lit.
They are fully lit at one end and barely lit at the other, with a little flicker.
I will attach some photos later.
No loose wires, tested 8 lamps already and all of them experience the same problem on both inverter transformers. I think there is not enough power to the transformers, but i don't know why.
I checked the voltage on f301 again and it is 13,3v.

[budm]

Re: Samsung 2253LW

Half lit lamp means it is not getting full voltage to the lamp. If it does that with known good the test lamp (bad wire on the lamp can also cause the same symptom), then the problem will be in the inverter.

[BigDaddyAdy]

Re: Samsung 2253LW

Yep, that's what i'm thinking. I will need to do some more measurements.

[BigDaddyAdy]

Re: Samsung 2253LW

Done. Fixed it!
One of the 8309 was bad. Although it looked ok on cold test, it was giving only 0.5V on output. Luckly when i bought them i took 10 pcs. Replaced the 8309 and now i have 8.5V
The lamps light fully now, and the monitor is working perfectly.
Thank you for all of your advises.

[selldoor]

Re: Samsung 2253LW

Hurray!! That is great news - well done. Should be a good help for others with this problem as well.

[jahjhai]

Re: Samsung 2253LW

That's great big daddy now my only hope is buy that chip 8309...I'm definitely sure that it will fix my problem.
Sell door sorry for the delay I am busy at work I got no time checking the parts

[budm]

Re: Samsung 2253LW

Thanks for posting the fix, but I thought you have already replace the 8309 and the caps already. Bad new parts then?

[jahjhai]

Re: Samsung 2253LW

the thing i see in that surface mount components are 334 and ZDE i dont know what it means.. but that is what i can see on it..