17ips19-5 no backlight - vivax tv

[6ot4hr]

Hi guys, i have a Vivax tv set with 17IPS19-5 PSU. There is picture visible on the LCD when i use flashlight, but no backlight.
Two leds on LED backlight strips were dead - shorted so i replaced them, but no luck with backlight. After replacing the leds i tested each of them and they all work. There are totaly 22 leds connected in series (2 strips X 11 leds).

Strange thing is, there is 26V on PL501 power connector, but the +26V is on black wire and not the red when measuret to the chasis ground

Shouldn't there be more, like 80 or 90 V since all the leds are in series?

[ReeceyBurger123]

Re: 17ips19-5 no backlight - vivax tv

Led driver Ic likely failed not turning the mosfet on for the boosted led voltage. Have you an image of the underside of the board ?

[srle77]

Re: 17ips19-5 no backlight - vivax tv

seem to have the same problem. power board is 17IPS19-5 and main board 17mb82

[ReeceyBurger123]

Re: 17ips19-5 no backlight - vivax tv

seem to have the same problem. power board is 17IPS19-5 and main board 17mb82

Planning ln diagnosing it ?

[ReeceyBurger123]

Re: 17ips19-5 no backlight - vivax tv

seem to have the same problem. power board is 17IPS19-5 and main board 17mb82

Planning on diagnosing it ?

[kiko1]

Re: 17ips19-5 no backlight - vivax tv

on 90% of these vestel PS-s + and - are reversed(+black and -red)
I think you can't measure voltage...it shuts down without load.

[srle77]

Re: 17ips19-5 no backlight - vivax tv

I am planning to fix it
tv wont turn on. It goes into standby(red light) when main power is switched on, but when i press the change channel button to turn the tv on itself and to bring it out of standby it flash several times(standby diode) and shows no picture and goes to standby. When I open it up i can hear buzzing from the power supply board inside when powered on. I suspect the fault to be somewhere on that main board. The board is vestel 17ips19-05 and main board 17mb82.Tv is Vox 32883 Visually trhere is nothing wrong with the board. I measured the voltage for the LED driver, between the chassis and red is about 2v and between chassis and black 22v.

not to forget, I changed two diodes on led panel

[srle77]

Re: 17ips19-5 no backlight - vivax tv

Planning on diagnosing it ?

I am planning to fix it