Issue on DC/DC chip on Samsung UE55MU9000 motherboard

[totof]

I have a problem with my Samsung UE55MU9000T TV, which is out of order. The TV starts up normally, but after about a minute, horizontal lines begin to appear on the screen, and after another minute, only horizontal lines remain.

I noticed that the DC/DC converter on the motherboard (BN41-02570B) gets slightly warm, and when it reaches approximately 43 degrees Celsius, the horizontal lines appear. If I cool the converter with a freeze spray, the lines disappear, but of course, they reappear after a few seconds. I disconnected the LVDS cables and observed that the temperature of the DC/DC converter increased, just as it does when the LVDS cables are connected.

I installed another motherboard initially without connecting the LVDS cables to monitor the temperature of the DC/DC converter. I observed that the converter did not exceed approximately 32 degrees Celsius. Next, I reconnected the LDVS cables, and the TV worked well for 5 minutes before horizontal lines appeared. I concluded that the original motherboard was faulty due to the panel, which also burn the replacement motherboard.

I would like to perform further tests, for example, to verify that a SMD component on the panel is not the cause. To do this, I would like to replace the DC/DC converter, part number VPM1GMA, but I can't find it. I only find part numbers VPM1RT, VPM1R0A, VPMS2RT, or VPMS3RT.

Since I haven't found a datasheet for this component, do you know which ones are compatible with the VPM1GMA model ?

Thank you

[Diah]

you have short inside the Display Glass at CKV rail.. nothings you can do only Tape masking.. try first with top LVDS

[totof]

you have short inside the Display Glass at CKV rail.. nothings you can do only Tape masking.. try first with top LVDS

Thank you, I willl try tomorrow. I can try without replacing VPM1GMA component on motherboard ?

[lotas]

What makes you think that the problem is in the T-CON controller (VPM1GMA)? Install a jumper between the FB_TRDY_1 and FB_TRDY_3 test points and check each half of the panel by disconnecting one LVDS cable.