Sceptre X322BCB0359

[nstlfrk]

Ok here is another LCD I am playing with.

When you plug it in the red standby light comes on and when you hit the power button it turns to Blue indicating the TV has turned on . But there is no picture or sound.

I had a second main board so i installed it and the Power supply seems to work as it should
Can you all help me out on this one as well?
Thanks

Here is pictures of all the boards.

[budm]

Re: Sceptre X322BCB0359

So what DC voltage right at the two legs of the 450VDC main filter cap laying on its side when you turn on the TV? Did you see backlights flashes on for seconds?
Any voltage labels at the connectors on the power supply board?

[nstlfrk]

Re: Sceptre X322BCB0359

It is only at 160vdc proly an issue right there.
There is labels but all they say is v+ v- and they all have voltage where they say v+
I hav another power supply I will try it real fast

Oh yeah no it never flashes just stays black

[nstlfrk]

Re: Sceptre X322BCB0359

Same outcome with the other power supply 160 dcv at the large cap

[budm]

Re: Sceptre X322BCB0359

If you turn on the TV and the cap is still showing only 160VDC, then the PFC Voltage booster circuit is not working or the power supply board is not getting PS_ON signal from the main board, the inverter circuit will not work until the voltage is boosted to around 370~400VDC range.
We need to make sure if the power supply is getting the PS_ON from main board next, that is why I asked for labels on the connectors.

[nstlfrk]

Re: Sceptre X322BCB0359

if you turn on the tv and the cap is still showing only 160vdc, then the pfc voltage booster circuit is not working or the power supply board is not getting ps_on signal from the main board, the inverter circuit will not work until the voltage is boosted to around 370~400vdc range.
We need to make sure if the power supply is getting the ps_on from main board next, that is why i asked for labels on the connectors.

[budm]

Re: Sceptre X322BCB0359

OK, I see the PS_ON PIN, so put black probe of the meter to the TV metal chassis, red probe on the PS_ON pin. When TV is OFF it should be <1VDC, when TV is ON it should be >2VDC.

[nstlfrk]

Re: Sceptre X322BCB0359

When it is off it shows 0 and when you urn it on it goes to 4.55

[budm]

Re: Sceptre X322BCB0359

OK, so both of your power supply PFC are not working. Is the spare power supply known to be good?

[nstlfrk]

Re: Sceptre X322BCB0359

Yes the one cam out of another TV with a cracked screen it turned on.
I have another main board as well but for some reason when you turn on the tv it will not let you turn it off.

[nstlfrk]

Re: Sceptre X322BCB0359

OK, so both of your power supply PFC are not working. Is the spare power supply known to be good?

It seems that both power supply's and main boards have the same affect.
The only difference is one main board lets you turn the tv off and the other will not.

[budm]

Re: Sceptre X322BCB0359

At least one main board does send out PS_ON of 4.55V to the power supply board.

[nstlfrk]

Re: Sceptre X322BCB0359

At least one main board does send out PS_ON of 4.55V to the power supply board.

They both do.

[nstlfrk]

Re: Sceptre X322BCB0359

I actually have 2 of everything.
It cant all be bad.
Well I guess it could.

[budm]

Re: Sceptre X322BCB0359

I look at it logical as the way the power supply operate and what it needs to function. May be some one else can chime in if they have the same power supply. I test the power supply by itself by forcing the PS _ PIN to turn on the power supply.
https://www.badcaps.net/forum/showth...supply+testing

[nstlfrk]

Re: Sceptre X322BCB0359

I look at it logical as the way the power supply operate and what it needs to function. May be some one else can chime in if they have the same power supply. I test the power supply by itself by forcing the PS _ PIN to turn on the power supply.
https://www.badcaps.net/forum/showth...supply+testing

Thanks for the info
I did just see that on that large cap where it read 160v after a few seconds it drops to 0v. Does that help at all or is that to be expected?

[budm]

Re: Sceptre X322BCB0359

That 160VDC on the cap should always be there the minute you apply 120V to the power supply board, that voltage (160VDC) is used to run the +5STBY power supply which is always on power supply.

[nstlfrk]

Re: Sceptre X322BCB0359

With my Fluke it is always there must a a dead or going dead battery in my cheaper meter.

What do you think about the start up caps being the issue?

[johnboy1313]

Re: Sceptre X322BCB0359

Try unplugging the t-con board from the panel. Maybe you have a short in the panel keeping eveything else from coming on like it should.

[budm]

Re: Sceptre X322BCB0359

"What do you think about the start up caps being the issue?" for the standby +5V? You are getting steady +5V to fed the main board so that will not be it.