Quadro tft 37kl25 hd

[nbdy]

Hi

Got the vestel 17pw20 v2 power source ...

The 24V is on for 3-5 sec,then drops to 0.6V

The blue (on) should be 5V but is 0.44V

Any one knows what to check

The 15nF/4700uF/220uF/1uF/4,7uF capacitors changed, the resistors 6193 are all ok

thx

[nbdy]

Re: Quadro tft 37kl25 hd

Another problem, the tv stays on for 10-15 minutes then shuts down, is the motherboard faulty or somthing else

I have all the voltages from the power supply

Thx

[Agent24]

Re: Quadro tft 37kl25 hd

Photos?

[ReeceyBurger123]

Re: Quadro tft 37kl25 hd

Poll cap failure is my bet, upload some images please.

[nbdy]

Re: Quadro tft 37kl25 hd

Sorry was on a field bussines,here are the pics:
the main board

https://www.dropbox.com/s/2mbm9u6kpf...71719.jpg?dl=0

the power supply board

https://www.dropbox.com/s/19vof47of1...71724.jpg?dl=0

working just fine,and

https://www.dropbox.com/s/b92slkmtcz...71933.jpg?dl=0

goes to standby mode

https://www.dropbox.com/s/rwyka7p7on...73018.jpg?dl=0

this is my first upload to cloud,say if you don't see the pics

the tv works for about 5-10 min and goes to stand by

after 3-4 times turnning it on it goes immediately in stand by



thx

[Electronic Handyman]

Re: Quadro tft 37kl25 hd

This is just my opinion and it could be a faulty regulator etc but I'am wondering if you've gone over the power supply board and checked the soldering connections bec it sure sounds like either a bad cap or a bad connection or a combo of both.The caps that you replaced did you use Low ESR good quality caps? Dis you check the other parts that are connected to any known bad caps that you have changed? Did you change all the caps close to the heatsinks? When you double check the board be sure to look at all the hot spots very closely.When the set kicks off if you let the set sit unplugged for awhile does it start up and perhaps work longer?Again from what you're mentioning it could be a cap that is not holding it's charge properly or a solder connection that is disconnecting itself after it gets hot etc.Don't forget to check the regulator connections too.

[nbdy]

Re: Quadro tft 37kl25 hd

when i turn it off (power button) and back on,the tv works for 5-10 min again

the caps changed are the best i could get in croatia

didn't change all the caps near the heatsinks

checked the solder connections,they all where ok

[ReeceyBurger123]

Re: Quadro tft 37kl25 hd

Checked the Polly caps above the transformer ?

[dick_barton]

Re: Quadro tft 37kl25 hd

I had a similar faulty power supply and it was one of the smaller electroytic capacitors but I cannot remember which one. Check the ones that I have highlighted. It had gone high ESR approximately 17 ohms.

[ReeceyBurger123]

Re: Quadro tft 37kl25 hd

You need to check the Poly caps at the top of the Psu as imaged, they can cause this issue:

[nbdy]

Re: Quadro tft 37kl25 hd

think it are the poly caps,but till monday nothing,gota buy them

thx for now

write back when i change the capacitors

[nbdy]

Re: Quadro tft 37kl25 hd

You need to check the Poly caps at the top of the Psu as imaged, they can cause this issue:

I had a similar faulty power supply and it was one of the smaller electroytic capacitors but I cannot remember which one. Check the ones that I have highlighted. It had gone high ESR approximately 17 ohms.

Changed both electrolytic and the poly ...

the tv works for 50-60 minutes and goes to stanby...

when i try to turn it back on it goes to stanby at once

[Kilroys]

Re: Quadro tft 37kl25 hd

Had a PW20 that went to standby after about an hour.
It was ic807 which was temperature sensitive.

[dick_barton]

Re: Quadro tft 37kl25 hd

So you have an improvement on the original 10 - 15 mins. Have you tried using freezer spray on the power supply components to see if you can bring it back out of standby.

[nbdy]

Re: Quadro tft 37kl25 hd

Sorry I have a lot of work outside my home ...

IC807, have to look ...

I dodn't try to use a freezer spray,but after a minute if you turn it on,it works for another 30-more minutes

[nbdy]

Re: Quadro tft 37kl25 hd

Changed the IC807, all right now ...

TV works

thx all for help

[budm]

Re: Quadro tft 37kl25 hd

Thanks for the follow-up, so what is the P/N of this IC807? It will be good to know what the function of that IC is and what DCV we get when it is not working.

[dick_barton]

Re: Quadro tft 37kl25 hd

IC807 looks like it's a KA3525A which is an SMPS CONTROLLER, 16-DIP

http://uk.farnell.com/fairchild-semi...|match|p|plid|

[nbdy]

Re: Quadro tft 37kl25 hd

Sorry for late reply,I work off my home ...

Yes like dick wrote the P/N of IC807 is KA3525A

greetz