coby TFTV4028 blue ligth stays on and won't power on

[hmendez86]

Coby Tftv4028 I found a problem to that I change one regulator and it turn on good nothing wrong but the thing is when it's unplug the cord it does the same thing blue light lit but won't power on...I check the regulators and they check good... I know the main is good...theres a problem on the turn on switch and there were am lost.....there mp14280dp can be that the problem...

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

[Nick's Tvs]

Re: coby TFTV4028 blue ligth stays on and won't power on

what kind of voltages do you get out of the power supply? When you press the power button, does the button ASSy change the voltage being sent to the main board or do all the voltage lines going to and from the buttons stay the same no matter what button you press?

[ReeceyBurger123]

Re: coby TFTV4028 blue ligth stays on and won't power on

You need to stop making threads, this is the 4th one if you wait people will help you. Check the Pson voltage going to the Psu.

[budm]

Re: coby TFTV4028 blue ligth stays on and won't power on

Is it the same as this one and the others?
https://www.badcaps.net/forum/showth...t=53484&page=2

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

The other thread was for a model 4025 and I fix it was the power and it is working fine.....now this is a 4028 bit diferente power and main....

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

When I press the power nothing does, but when I plug the tv the blue light comes on like tv was on check the power and I have 24v for the inverter..and 5v for stanby....

[budm]

Re: coby TFTV4028 blue ligth stays on and won't power on

The other thread was for a model 4025 and I fix it was the power and it is working fine.....now this is a 4028 bit diferente power and main....

So you did not post the follow-up as to what you have done to fix the problem in that thread after 33 posts?

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

Ps on I got 4.2v and 5vSB 4.9v this is with blue light on it won't change even if I press power

[budm]

Re: coby TFTV4028 blue ligth stays on and won't power on

Ps on I got 4.2v and 5vSB 4.9v this is with blue light on it won't change even if I press power

That means you have main board problem.

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

I did not just I replace the power supply and fix the problem on 4025...but wanted to check if I can fix the power and saw It was more cheap to buy a working power that to fix it

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

But the main board when I move parts or change a cap it work fine even if a press on and off..once it is unplug u won't able to turn on again blue light keep lit again

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

this voltage regulator I change it and work with on and off ...just right away when I unplug the cord it wont power the cap above the grey resistor change it and work again.....just work until I unplug the cord.

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on

On the ps on on power supply y get 38.6v?? And when I turn on I get 4.21v??

[hmendez86]

Re: coby TFTV4028 blue ligth stays on and won't power on





the last picture is when I unplug it and blue light comes and won't come on