Samsung T260 no display

[bazzuk]

Hi All
After my success in repairing a samsung games monitor with a 2 s back to black issue i thought i would try something harder.

So with that in mind i have a samsung t260 monitor which doesnt display a picture. This has come from a samsung service centre and was tested by them with the result that the panel was broken.
Have found a replacement panel but here is my question.

The controller board on the back of the CHIMEI lcd panel has a surface mounted component with an id of F1. I am assuming this is a fuse of some type but the component only has the number 3 written on it so i thought it might be a capacitor of some description. The 5v input voltage from the main pcb goes in to a plug then is sent through F1 and another circuit to get it 3.3v as this is the standard lvds voltages for panels. So the faulty panel may just be a blown fuse.
I have read up on lvds loads and found the lcd panel circuit board has an lvds receiver and this is powered by the voltge from the circuit the mysterious F1 us from.

Could a blown fuse be the issue or would it be unlikely the component is a fuse?

regards

Bazz

[tom66]

Re: Samsung T260 no display

F1 is almost certainly a fuse and "3" means 3A or 3.15A probably.

[jetadm123]

Re: Samsung T260 no display

I may be stating the obvious, but have tried using your meter to check F1?

Also, your description of "doesn't display a picture" is extremely vague. Does the power led light up? Power supply outputting proper voltages? Any additional observations would be helpful.

Photos using "manage attachments" would be helpful.

[selldoor]

Re: Samsung T260 no display

What did it do when it had a broken panel in and was switched on?
Did you get a panel with EXACTLY the same model and reference number as the old one.

[bazzuk]

Re: Samsung T260 no display

Hi All

Yes i tried the test of F1 its open circuit.
The monitor powers on and power light comes on the back lights light up ok also.

The replacement panel is EXACTLY the same except the broken one is rev 2 and the replacement is rev 1.

Just wondering if it is a fuse would save £'s rather than getting new panel. I am guessing the circuit board is the lcd panels driver circuit and the large chip is the LVDS receiver.

Regards

Bazz

[selldoor]

Re: Samsung T260 no display

Yes it is a fuse - if it is open circuit , that is , reads the same as holding your probes apart then yes it needs a new fuse.
Only problem might be we dont know what caused it to blow so it may blow again so buy 2.

[tom66]

Re: Samsung T260 no display

Test from the right end of the fuse to the casing of the screen on ohms, should read infinite. Note several tantalum caps - yellow/orange things - these can fail short but they usually burn themselves when that happens.

[bazzuk]

Re: Samsung T260 no display

aha cool thats what i thought was busted, just need to figure out what blew it.

bazz

[bazzuk]

Re: Samsung T260 no display

how do i figure out which one to replace it as the 3 marking doesnt help me much, all the markings i can find relate to letters not numbers?

bazz

[selldoor]

Re: Samsung T260 no display

Just get a 3amp smd fuse could be 24 or 32 volts doesnt really matter but
needs to be same physical size.

[tom66]

Re: Samsung T260 no display

Or use a 3-5A automotive fuse as a temporary fix.

[bazzuk]

Re: Samsung T260 no display

Hi Guys

HEre is the update, i replaced the panel with a newish one, i checked to make sure the fuse on the newish panel was intact which it was. Put the whole thing back together and same problem exists.

You get no picture when you connect the monitor up to the computer and switch to the new monitor. So with this in mind it would seem that there are more than one problem here and its not just the panel.
Had a check of the main control board and found all the expected voltages are there asi only have a multimeter at the moment.
To test the main board according to the service manual i need to do the following

Check if R, G and B inputs are measured at R106, R110 and U2593.
Check if Hsync and Vsync are measured at R115 and R116.
Check if Hsync and Vsync are measured at pins 32 and 33 of IC202.
Do output signals appear at pins 8 to 30 of CN400?
Is DC 5V measured at pins 1, 2, and 3 of the CN400?

If at each step that test is ok then go to the next one my problem is how do i check these will i need an ocilloscope and if so which kind eg pc based, standalone or what?
I dont know what sort of voltages will be at these points or what frequency so not sure which one i will need if any.

Also could it be that there is no firmware on the monitors system board would this cause this sort of issue IE what is a DDC and do i need one?

Hope you guys can help cause yes i know i said i wanted something more challenging but not something impossible?

Bazz

[bazzuk]

Re: Samsung T260 no display

here are some pics so we know whats what

bazz

[selldoor]

Re: Samsung T260 no display

Pic 1 does the monitor stay like that for 5 minutes with just the back light on?
can you get the osd menu on
Do any of the controls work including on/off.
Not sure I understand your opening bit about the pc. Do you have the pc on and connected to a working screen then simply unplug the vga cable and plug it iinto this?
If using vga have you tried hdmi or Dvi input

[bazzuk]

Re: Samsung T260 no display

Hi Selldoor
Yes the moitor stays on like the pic all the time, none of the menu keys make any picture come up and yes i unplugged from a working monitor using the analogue and DVI connectors. The only control on the monitor which works is the on off button.

Bazz

[selldoor]

Re: Samsung T260 no display

When you say you still have the SAME problem Did the old panel light up as this one does.
Most of the pics are too blurred for troubleshooting and important bits at the edges are cut off.
Next step would have been to ask what voltages you were getting on the various connectors but cant make out what they say and one is cut off at the top.
To follow the SM you would need special test equipment and an o-scope, but much testing can be done without, providing we can see what we need you to test.

[bazzuk]

Re: Samsung T260 no display

Hi
I tested all the output voltages from the power board they are all correct. The 5v power line to the panel is also present. The previous panel lit up also so i am guessing the lamps and suply are fine i just dont get any picture.
From these results i would guess the main control board has had it.

Bazz

[selldoor]

Re: Samsung T260 no display

Possibly but I cant see the pic clearly - if you want to troubleshoot it post good clear pictures.
Read this by retired caps
https://www.badcaps.net/forum/showthread.php?p=261329

[bazzuk]

Re: Samsung T260 no display

Another update the monitor is recognised by my computer but still no picture, i still think the main control board has had it.

will try something else and post better pics but that aint easy with my camera