no backlight supply volts hisense ub50ec591uwt

[Diah]

Re: no backlight supply volts hisense ub50ec591uwt

parts ordered i will update asap

yours PSU working on almost the new standard circuit design by producing certain operation Voltage which converted VIA DC to DC step downer at MB, like other brands LG OLED / nano cells / U LED Panels.. which it need another method to run the PSU as stand alone.

So i think you and any other members whom don't have yet ...need to have DC to DC step downer PCB, they are cheap less than 3USD with wide range in and out V.. so you can exam yours PSU and BL circuit with out need the MB to narrow any future issue it may accuse by MB

[jimbofz]

Re: no backlight supply volts hisense ub50ec591uwt

finally fixed .
the led driver ic LX27901 ID was replaced ,
i had to get it from a supplier in Spain ,so sorry for the delay in this post ,
as you all know it seems to get harder with every job to source parts.
thanks all for your help ,
.ive learned not to trust what some customers say ,
as this tv clearly had been got at by some previous attempt to fix .(two leds had been replaced)
one of the foils feeding the panel had a slight tear in it add was damaged,
,(if you flexed it gently we had lines and noise in left hand side of pic) but i managed to replace it,after reducing the backlight settings from 100 to 25% still a good pic .thanks to all who took the time to help

[giorgi711]

Re: no backlight supply volts hisense ub50ec591uwt

Can you please explain me, what does SW(BL_EN) abbreviation means? What is it for ?

In order to measure voltage on sw pin, I connected the black wire of multimeter to gnd pin(num. 1 on XP805 on image) and red wire to SW pin, after that one of capacitors(25V) swollen and blew smoke.

Before i did that, voltage between 12V pin and gnd was 24V, and between 16V and gnd was 32V.

Here is scheme of PSU of hisense tv.

[giorgi711]

Re: no backlight supply volts hisense ub50ec591uwt

Scheme image has poor quality, see PDF file in attachments.