Hisense LCD42W60P Television

[angelos]

Hi Guys,
I have this 2008 lcd tv that uses ccfl lamps. The tv is stuck on standby. This is what I have noticed. The standby 5Vs voltage is not 5V but rather 3.28V. There is a 14V rail as well but that measures ok. I put my volt meter on the 5Vs rail and switch on the 220Vac. I noticed that the 5Vs rail goes to 5.1V and quicky changes to 3 28V and steady.
I unplugged the main board and ccfl lamp wires and tested the power supply separate from the tv without load and put a 470 ohm resistor to the stby rail to force the tv on.
1. Pfc circuit activates and mains smoothing cap is at 389v DC.
2. The 5vs rail is 5.1V
The 14v is at 16v (probably no load)
You think there is a short on the main board, right. I checked that, no short or low ohms.
3. I heated all the electrolytics and it made no difference. I even checked them with my esr meter, no fault
Then, if you look at my photos you will notice a voltage rail specification. The 14V is rated at 1.5A.
I put in a large resistor as a load on the 5V and 14V rail. I drove it at 50% of rated current and the PSU 5Vs rail dropped to 2.8V.
It appears the set cannot run under load.
the pwm chip is 1207AP. I think its NCP1207AP
Is there anything i can check? I do have a scope. I can check if the set is chopping the dc correct or running in burst mode for example. I suspect a zener or resistor has changed, not sure. Sorry. I am not at work now to take clear full photos of the PSU.
Any suggestions?
regards
Angelos

[lotas]

Maybe the firmware on the motherboard has crashed, what is the motherboard number?

[Davi.p]

Hi Angelos, the fault is within the PS board for sure, if you loaded the 5v_M (m=main, s=standby) and it dropped then watch the main stage and follow the feedback circuit, on the secondary you have to replace the shunt refulator (TL431 or like).. other issues can reduce the voltage, for example, if the tv set was in other's hands, he can have changed the big resistor less.than a ohm on the mosfet source for a wrong value, etc etc..

ps: check the capacity of the main smoothing 450v capacitors

[Davi.p]

I think too many people sleeping in this site...

[angelos]

Hi Davi,
I am definitely not having a nap.
I am looking for the NCP1207AP chip, i have alrerady got TL431 and also PC817 but i want all the parts before i reopen the tv.
I need to get it sorted out. Unfortunately i only get to work on weekends to do repairs as i have a primary job.
I will check you informed when i have more info.
Thanks for keeping an eye on me.

Regards
Angelos

[nomoresonys]

Well what I think he meant, is that everybody here except for him is stupid.

[Davi.p]

"Nomorecazzy":
someone helps this person to find the users filter function, so i do not read his useless posts again.. i have read also his post where he abandoned the forum (for the 30th time), then he deleted it because he has nothing else to do than enter here with all exept real technical questions.. your posts value=0..


Angelos: ok leave at least a sign you have read the post.. there are many and many dead threads where i put my effort and no more life in discussion after.. sad..
depends on each user but i observe this always more..

[nomoresonys]

I think too many people sleeping in this site...

I know you can't comprehend English, no matter how long you have been trying so then why don't you explain what you meant by that remark about everyone sleeping. nitwit.

[Diah]

I know you can't comprehend English, no matter how long you have been trying so then why don't you explain what you meant by that remark about everyone sleeping. nitwit.

don't bother with rubbish poster... " users are sleep "

[Davi.p]

And the other one demented at the follow, 2 cancers at price of 1

[nomoresonys]

don't bother with rubbish poster... " users are sleep "

You are correct sir, I have yet to see him solve anything but the simplest problems, yet he claims to be a master tech, laughable.

[CapLeaker]

don't bother with rubbish poster... " users are sleep "

Right on.

[CapLeaker]

You are correct sir, I have yet to see him solve anything but the simplest problems, yet he claims to be a master tech, laughable.

Like diah already said: don’t even bother. It’s wasted time you don’t get back. Master tech? My

[angelos]

"Nomorecazzy":
someone helps this person to find the users filter function, so i do not read his useless posts again.. i have read also his post where he abandoned the forum (for the 30th time), then he deleted it because he has nothing else to do than enter here with all exept real technical questions.. your posts value=0..


Angelos: ok leave at least a sign you have read the post.. there are many and many dead threads where i put my effort and no more life in discussion after.. sad..
depends on each user but i observe this always more..

I am here Davi, i am going to work on the unit on Saturday. Then i will update.

Regards
Angelos

[Davi.p]

Yes, if the band of bastards do not pollute every discussion, maybe the bar are closing all.. it's light and clear , some like Nomorecazzy enters threads only to attack.. they have nothing to do all day..

[nomoresonys]

Like diah already said: don’t even bother. It’s wasted time you don’t get back. Master tech? My

+1,000,000

[nomoresonys]

Uh oh, careful you guys, davi boY might challenge you to a MASTER TECH DUEL. hes gonna lose tho. I wish Budm was still here, he could always point out how wrong this guy is too.

[CapLeaker]

Uh oh, careful you guys, davi boY might challenge you to a MASTER TECH DUEL. hes gonna lose tho. I wish Budm was still here, he could always point out how wrong this guy is too.

I miss Budm too.