Author Topic: Samsung 2443bw LCD monitor  (Read 5288 times)

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Offline meeslef

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Samsung 2443bw LCD monitor
« on: April 12, 2015, 03:24:57 am »
Hey guys,

Just been given one of the above.

Fault: powers on, then gets crazy horizontal lines down a third of the screen, you hear a crackling noise then the backlight powers off.

Backlight is definitely off, can still see faint picture with torch.

Tried replacing most of the caps (none obviously bulging, leaking etc) (replaced caps feeding inverter), still fails, crackling noise definitely coming from inverter module (this monitor has integrated PSU / inverter). Part marked tms93682ct, doesn't seem to exist on the internet.

i would very much like to get this working again as the LCD panel is very nice, to replace the full PSU / inverter would be quite expensive, does anyone have any suggestions as to how go about further diagnosis / repair of faulty board ??

I haven't yet replaced the main AC cap or a couple of small caps elsewhere on the board and I can't seem to find a replacement for the inverter module. (I removed it from circuit and the secondary resistance tests pretty much the same / not open or closed.)

Any thoughts gratefully received.. :)
 

Offline wraper

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Re: Samsung 2443bw LCD monitor
« Reply #1 on: April 12, 2015, 05:38:30 am »
Horizontal lines on the LCD shouldn't be caused by the backlight issues. But backlight turning off can be easily caused by unstable power. Probably something wrong with PSU. Check capacitors on the primary side (mains side) too.
But if you wish to check the backlight inverter itself:
First of all check secondary windings of inverter transformer. Both of them must have about 1k resistance. If one of them is open or resistance of them is noticeably different, it is faulty. Usually many other models of transformer can be used as replacement, http://www.ebay.com/sch/i.html?_odkw=8TC0049901GP&_from=R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.X8TC0049901.TRS0&_nkw=8TC0049901&_sacat=0 seems to be compatible.
 

Offline tec5c

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Re: Samsung 2443bw LCD monitor
« Reply #2 on: April 12, 2015, 06:13:13 am »
Are you able to take a photo of the fault? Depending on the colour, length, thickness etc of the lines can tell you more about the origin of the fault.

It could even be something as simple as a bad LVDS connection - caution must be exhausted when plugging/unplugging an LVDS cable as they are more fragile than standard cables.

You said you replaced most of the caps, does this include the electro. caps on the main board? I believe there are 4 of them. If you have an ESR meter, it might be a good idea to do a quick check on the electro. caps on the main board as horiz. lines are mostly associated with this board rather than the power supply board.

Also, photos of the inside of the monitor would be helpful.
« Last Edit: April 12, 2015, 06:24:18 am by tec5c »
 

Offline meeslef

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Re: Samsung 2443bw LCD monitor
« Reply #3 on: May 01, 2015, 03:49:24 am »
Hey guys,

Thanks for the replies, i ended up destroying my DMM testing this out so i've only just got back to it.

Finally stripped the LCD panel completely down, and found an arcing power lead feeding one of the CFL tubes... you could actually see it arcing across the bench once the panel was apart....  :-[

A great deal of patience and sanding later reattached the wiring and it's back and running...

We can consider this closed.
 

Offline jorisc

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Re: Samsung 2443bw LCD monitor
« Reply #4 on: May 14, 2015, 11:03:47 am »
My 2443bw lcd screen is also broken, it has vertical lines on the right side of the screen, probably because of this connector:

Because when i push on it, sometimes the screen works again for a couple of minutes
It is located in the left corner of the screen under the metal cover:

(not my own image)

Is it possible to fix this connector?
« Last Edit: May 14, 2015, 11:07:22 am by jorisc »
 

Offline Shock

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Re: Samsung 2443bw LCD monitor
« Reply #5 on: May 16, 2015, 07:08:42 am »
Is it possible to fix this connector?

If you ever have questions don't thread hijack, start a new thread, remember this forever and start your own thread if you need more help. The internet works better this way.

It looks like it's bonded, it's done with a conductive glue/resin (likely) or solder under heat, very hard to rebond, you probably need specialist tools and a microscope. The easiest workaround is to pack something on top so it's evenly pushed down and makes good contact, a temporary fix though.

Attempting to reheat and it could end up worse, the first time it's bonded it would normally have fresh glue/resin and the heat and cool cycles would be closely controlled.
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM       >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 

Offline wraper

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Re: Samsung 2443bw LCD monitor
« Reply #6 on: May 16, 2015, 03:41:52 pm »
You could try Z-axis conductive tape http://www.ebay.com/itm/261866296847
Though you would need to remove existing flex cable without any damage and perfectly clean all of the contacts. Then apply with great precision. Doesn't sound like a great possible success rate.
 


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