17ips20 diagnosing

[vinceroger69]

Re: 17ips20 diagnosing

have you tested the leds individually with a power souce? maybe you have some shorted/failing

[formant84]

Re: 17ips20 diagnosing

Further update:

Okay there was a problem with my hdmi adapter. The computer now detects that the to is connected but I get no picture or sound. Voltage to LEDs is okay, backlight seems to come on but rather dimly. Tried shining a torch at the screen, no sign of any kind of image.

Could this be the power board? Or am I looking at a logic board issue?

[formant84]

Re: 17ips20 diagnosing

UPDATE: The thought occurs that it's not powering down the logic board, but maybe exiting standby mode causes a fault either in the power going to the logic board or on the logic board itself? The logic board is a vestel 17MB55.

[formant84]

Re: 17ips20 diagnosing

Hi Sorry to hijack this thread but I have an ISIS branded 39" tv with this power board and I have the weirdest problem. When I press the power button, the power/standby light comes on and power goes to the logic board because my laptop detects the display over HDMI.

But when I press the power button again, the laptop can not longer detect the TV but suddenly it powers up the LEDs, going up to about 190v then down to a steady 115.5v

So basically it seems to power each part of the TV alternately, but not at the same time!

Any suggestions? I'm stumped.

[Boberko]

Re: 17ips20 diagnosing

Hi, i have a durabase tv DL40f180x2 with board 17ips20.
boad i tv is completly dead. Fusion F101 is blow and whole board is dead. I thing i try repair kit DEAD - q301 s/c

I buy second one, but seller send me diferent as i have. If i give it to tv, stanby diod is light. When i turn on tv, standby led is flashing.

Any idead what is wrong in first or second one board?

[ReeceyBurger123]

Re: 17ips20 diagnosing

Yeah you will need the repair kit as Vince linked

[Leslie W]

Re: 17ips20 diagnosing

Hi Reece,

I don't fancy my chances of soldering that kit on my board. I don,t remember you fixing one that way on your videos!

Anyway I have checked the diodes and:
D208 short

D209 short - these are the three together
D226 short
D225 short

D504 short - the one in the corner nearest led output

This looks similar to a fix in one of your vids.

What do you think?

Les.

[ReeceyBurger123]

Re: 17ips20 diagnosing

Dam it lol worth a shot anyway

[crt man]

Re: 17ips20 diagnosing

Yes then you have a backlight fault then, the Psu is fine if it goes up then drops. Take the panel apart and test the Leds as shown in the video.

Just an update on this took panel apart,
and there was 17 led's out including one
complete strip plus the rest have varied
degrees of brightness. Unfortunately the
panel got a crack so off to the tip with it.

Alan

[vinceroger69]

Re: 17ips20 diagnosing

Thanks flocko for your input also this mayhelp too
https://www.monolithicpower.com/Desk...cument?id=1263

[flocko]

Re: 17ips20 diagnosing

To repair the LED output side of the 17IPS20 you must look up the datasheet for the MP3394S 4 string driver to see how it works. check all SMD resistors around the driver for value and any that show to be outside of 5% should be replaced. I cannot give you any values as they change with the size of set and the number of LEDs per string. If you do change the driver (U500) I would also change the mosfet (Q502) Hope this is of help Flocko

[ReeceyBurger123]

Re: 17ips20 diagnosing

Sweet cheers Vince cant find the Sm now I had it a few days ago though

[vinceroger69]

Re: 17ips20 diagnosing

this kit reece seller flocko on this site
http://www.ebay.ie/itm/Vestal-17IPS1.../252437754233?

im sure flocko will know which resistors they are as he mentions them in his add

[ReeceyBurger123]

Re: 17ips20 diagnosing

No worries, cant seem to find it though will have a check shortly. If not find the parts/repair kit for it

[Leslie W]

Re: 17ips20 diagnosing

Cheers Reece you are a star!

[ReeceyBurger123]

Re: 17ips20 diagnosing

Awesome work glad it worked for you Also the fix would probably be to replace the led driver/controller also theres a few resistors for it that can go leaky will see if I can find the SM.

[Leslie W]

Re: 17ips20 diagnosing

Hi Reece Yes I read about the multitude of boards I got the number 23145828 off the board. TV is now fixed, also tuned the backlght to low as recommended by your good self.

I think I might have a go at repairing the old board as a learning experience. I will start tomorrow by checking all the diodes. I have a multimeter and I can solder.

Obviously the wheatstone bridge is working as I have 118 volts DC at the led connector. What else might be u/s in the pwm other than the diodes?

By the way thanks so much for your help my mrs is over the moon.

Best Regards

Les.

[ReeceyBurger123]

Re: 17ips20 diagnosing

No worries, btw you did order the one for that screen right ? As you cant just use any old 17ips20 in there.

[Leslie W]

Re: 17ips20 diagnosing

Thanks Reece

Just ordered one from ebay.

If it works I could send you the old one.

Cheers

Les

[ReeceyBurger123]

Re: 17ips20 diagnosing

Its part of the Pwm circuit, starts at higher voltage to start the strings but low current, the it lowers and increases the current to maintain proper brightness whilst the Pwm is working. Your Psu is faulty in your case.