17IPS20 No Led Voltage Solved With Video :)

[fredaelsadany]

Re: 17IPS20 No Led Voltage Solved With Video

HI ReeceyBurger123
very good work very good video thank you .
this power supply seemed to complicated ..but not it is not wil arranged diagram .
I have two comments :
first when you measure c127 it has 100 ohm parallel to it ...it shows false short cir
second if c525 (1uf/50v) is bad it wil stop backlight I send pic elastrate the reason for this .
I think all vestel ps are the same but this one is the worst .
again thank you for good work and video .

[ReeceyBurger123]

Re: 17IPS20 No Led Voltage Solved With Video

Cheers matey

[Wroxall Tony]

Re: 17IPS20 No Led Voltage Solved With Video

Thanks to your video about replacing LEDs I have now identified a duff LED and will have a go at my first LED replacement - when my hot-air soldering station arrives! Brilliant video. Many thanks, ReeceyBurger123. I may be 64 but I'm still learnin'!

[ReeceyBurger123]

Re: 17IPS20 No Led Voltage Solved With Video

Sorry I didnt see your first comment, good luck doing it keep us updated

[huzo]

Re: 17IPS20 No Led Voltage Solved With Video

Sorry for bringing up this old Post,but I have a problem with the board...it had no power whatsoever,so I found the dead 8n60 fet,I believe it's q301,replaced it ,and it started,but was blinking fast standby led...so I flashed new firmware via USB,but flashed wrong one so the picture is upside down,but with no backlight...I do have 115v at the caps for backlight,but 0v at the backlight connector...both fet are not s/c ,smd resistors are all ok...what could be the problem?mp3394?but the voltage exists at the caps...so I'm stuck at the moment with no ideas

[sordids999]

Re: 17IPS20 No Led Voltage Solved With Video

Hello
Having problems with this set 42hxt12u
No backlight +led starts at 190v then drops to 155v and stays there -led 11v

[sordids999]

Re: 17IPS20 No Led Voltage Solved With Video

Update:
Tested with backlight tester backlight comes on
Even removed the screen and tested each led individually and all good
LED sensor flashes red then goes to blue but still no backlight

[vinceroger69]

Re: 17IPS20 No Led Voltage Solved With Video

Update:
Tested with backlight tester backlight comes on
Even removed the screen and tested each led individually and all good
LED sensor flashes red then goes to blue but still no backlight

firmware?

[sordids999]

Re: 17IPS20 No Led Voltage Solved With Video

That's the thing I have a spare main and psu from a cracked screen tv same model and swapped them around and still the same the only option now is tcon board

[sordids999]

Re: 17IPS20 No Led Voltage Solved With Video

Fixed:
Red wire on led + I had no reading going to leds even though I had 155volts from psu found the positive connection needed gently crimping inside the legend found this by moving the wire the backlights would come on and off

[edoogle]

Re: 17IPS20 No Led Voltage Solved With Video

Hey guys, sorry to hijack a thread, but this kinda relates to my issue......

Im trying to fix a backlight issue on my sisters samsung 32W3453DB

after watching several youtube videos, I jumped in at the deep end and started replacing led's I thought were bad, but with no success.

after testing the 17IPS11 power board, I was only getting 25v out on the led supply so replaced this but Im still getting the same issue.

I dont have the voltage info from the power board to the main board so I'm struggling to diagnose the 17MB95 23186905 but I fear this could be the issue?

does anyone have the voltage to pin info for the connection from power to main board please

Thanks

Kev

[Willy6]

Re: 17IPS20 No Led Voltage Solved With Video

Hola buenas ante todo tengo un problema, por si alguien me pudiera ayudar, he mirado la corriente de salida a los led y me marca 204 v. Con -led y masa 12. Ya me ha fundido unos led. El problema es que estando en Stanby me sigue dando 192v entre los dos. En los diodos d211 me da cuando está conectada 12 v por el lado + y 150 v por el otro.la imagen se ve bien pero me funde los led y hace un ruido raro por detrás. Me podríais ayudar por favor

[johnboy183]

Re: 17IPS20 No Led Voltage Solved With Video

Hi Sorry to jump on to this thread but my issues are the same as above largely. I am trying to sort no backlights ona JVC LT50 TW60J with the dreaded 17IPS20 board. Have followed closely the many threads on this especially the excellent youtube video by ReecyBurger123 which was very helpful but seem to now have reached a dead end. The set has a working screen with an occasional flash of backlight at startup but most of the time backlight's remain stubbornly dead. I was convinced it was a LED problem so checked to find odd faulty LEDs but once all were fixed and and each strip tested and working I get no backlight on connecting up the whole series and firing the set up. The LED out from the board goes straight to 156v and remains there constantly. But no 180-190v startup voltage. With the LEDs in place I get 156v at the beginning of the LED circuit and 95v at the end of the LED circuit on the return to the board. Reading all the threads I am left with suspecting the startup boost. Any help if pointing me to the likely board culprits would be very appreciated as nearing wits end on this issue!

[diif]

Re: 17IPS20 No Led Voltage Solved With Video

How did you test the LEDs and strips ?

[johnboy183]

Re: 17IPS20 No Led Voltage Solved With Video

Tested individual LEDs using a 3.3 volt output on a PC PSU adapted as a power source.
Tested the strips ( 9 LEDs per strip) using two 12 volt batteries in series to give 24 volts - it works well.
Not sure how that information relates to my problem though? - unless your follow up message will explain.

[diif]

Re: 17IPS20 No Led Voltage Solved With Video

Tested individual LEDs using a 3.3 volt output on a PC PSU adapted as a power source.
Tested the strips ( 9 LEDs per strip) using two 12 volt batteries in series to give 24 volts - it works well.
Not sure how that information relates to my problem though? - unless your follow up message will explain.

Quite often people write they have tested the LEDs and they are fine but they haven't tested them at their working current and testing correctly reveals failures.

[johnboy183]

Re: 17IPS20 No Led Voltage Solved With Video

So do you feel that the LEDs may be at fault as not tested by an approved method?
As there is no 190 volt startup boost is that lack of boost unlikely to be the cause then?

[johnboy183]

Re: 17IPS20 No Led Voltage Solved With Video

Given the number of posts on this Vestel board in the forum I am a bit disappointed there has been very little in the way of answers to my question about the lack of boost voltage on my own board. Not sure if that is because key people have left the forum or they are just unavailable currently. Any help or thoughts on this problem would be very much appreciated.

[budm]

Re: 17IPS20 No Led Voltage Solved With Video

Hi Sorry to jump on to this thread but my issues are the same as above largely. I am trying to sort no backlights ona JVC LT50 TW60J with the dreaded 17IPS20 board. Have followed closely the many threads on this especially the excellent youtube video by ReecyBurger123 which was very helpful but seem to now have reached a dead end. The set has a working screen with an occasional flash of backlight at startup but most of the time backlight's remain stubbornly dead. I was convinced it was a LED problem so checked to find odd faulty LEDs but once all were fixed and and each strip tested and working I get no backlight on connecting up the whole series and firing the set up. The LED out from the board goes straight to 156v and remains there constantly. But no 180-190v startup voltage. With the LEDs in place I get 156v at the beginning of the LED circuit and 95v at the end of the LED circuit on the return to the board. Reading all the threads I am left with suspecting the startup boost. Any help if pointing me to the likely board culprits would be very appreciated as nearing wits end on this issue!

1) Can I see good clear straight shots of the whole top and bottom side of YOUR board?
2) "With the LEDs in place I get 156v at the beginning of the LED circuit and 95v at the end of the LED circuit on the return to the board." What do you mean 'at the end of the LED cicuit? Do you mean the Cathode return of the LED string? Your TV has only two wires to the LED string, correct? So if you have 156V feeding the Anode of the LED string and 95V on the Cathode return, that means the Vdrops of the LED string is only 61V! which is not normal.BTW, the measurement is done using chassis as the GND ref. for the meter, correct?
3) The schematic we have shows 24 ~ 80V (depends on PCBA) is for feeding the LED boost converter, you indicate that you have 156V so the boost converter is working but not high enough.
4) No LED connector in place, keep black probe of the meter on chassis, Red probe on the V+LED of the LED connector, what Voltage does it show when TV is off, then hit the power button and see what Voltage it goes up to.

[johnboy183]

Re: 17IPS20 No Led Voltage Solved With Video

Thanks for the reply and thoughts. I will try and take some good photos of board and post later today. Things have moved on slightly in that I have managed to get a good clean set of fully working LED strips from a reputable source but the fault remains - ie no backlights on at all and not even a brief flash of them.
I have set up now the complete array and boards on the bench and checked every connection point along the LED path from the board back to the board and to ensure no shorts to chassis etc.
With the array plugged in, black lead from Meter to earth ( Both boards earthed to each other) and red lead used to probe voltages along the LED circuit I get when power switched on:
166v instant blip (blink and you miss it)
156v at LED + connector on board
156v at + connector on 1st strip
138v at + connector on 2nd strip
121v at + connector on 3rd strip
102v at + connector on 4th strip
87v at + connector on 5th strip
71v at + connector on 6th strip
58v at + connector on 7th strip
48v at neg side of LED connector on power board.
When tv turned off using remote ( so no front blue light) LED + connector shows 3.7-4.2v (why?).

Led connector disconnected with no front blue light (as above) the 3.7-4.2v slowly disapates down to 0V
Then turn on TV with remote with LED cables disconnected I get very brief 166v followed by static 156v at LED+ connector on board.
I hope this helps you make some sense of the problem as I am running out of ideas. thanks for your help. Will send board photos soon