Toshiba 40UL605U Won't power on

[landyboy]

Picked up a Toshiba 40UL605U LED. Symptoms are when you hit power button all lights blink once and then nothing. Initial testing shows

5v 5.143
5v 5.143
G 0ohm
G 0hm
PWON 0
BLON 0
DIM 0
24v 0
12vcc 0
G 0 ohm
G 0 ohm
ACD 0

I'm thinking power supply issue

[notallbad]

Re: Toshiba 40UL605U Won't power on

why ps?

could be main ssb board, i.e no PWON signal

[tom66]

Re: Toshiba 40UL605U Won't power on

It's not turning the power supply on (PWRON) so I'd be aiming more at main board myself.

edit: notallbad beat me to it...

[notallbad]

Re: Toshiba 40UL605U Won't power on

by a whisker, hehe, sorry tom

[landyboy]

Re: Toshiba 40UL605U Won't power on

Can I jumper the 5.1 V to the BWON to turn set on?

[tom66]

Re: Toshiba 40UL605U Won't power on

PWON... yes. Use a 100 to 470 ohm resistor in series to limit the current.

[landyboy]

Re: Toshiba 40UL605U Won't power on

ok Jumpered from PWORN to 5.1v no reaction.

[tom66]

Re: Toshiba 40UL605U Won't power on

Check PWON actual voltage, and did you use resistor?

[landyboy]

Re: Toshiba 40UL605U Won't power on

yes 270 ohm resistor. Are you talking 5.143 voltage after resistor?

[landyboy]

Re: Toshiba 40UL605U Won't power on

when I apply voltage to the PWON it drops from 5.1 to .55v on the PWON side of the resistor with the main board connected

[landyboy]

Re: Toshiba 40UL605U Won't power on

When I jumper 5v to PWON I now get 12v on the 12vcc pin PSU connector to Main is disconnected at Main

[landyboy]

Re: Toshiba 40UL605U Won't power on

I also get the 24v on the psu

[tom66]

Re: Toshiba 40UL605U Won't power on

Main board is bad then, power board OK. You can also test LCD by using resistor in between 5V and BLON and DIM to make sure it is not cracked before you repair/replace main board.

[landyboy]

Re: Toshiba 40UL605U Won't power on

Just jumper those three? 5v BLON and DIM (with a resistor of course)

[landyboy]

Re: Toshiba 40UL605U Won't power on

And just for my understanding. Why must the DIM be jumpered also? I did try just jumper between 5v and BLON and the back lights did not come on. So I am assuming that's why the DIM is required as well.

[landyboy]

Re: Toshiba 40UL605U Won't power on

Ok unless I am doing something wrong I cant get the BL's to come on. I am jumpered from 5v with a resistor to BLON and then another straight jumper from BLON to DIM. Main board disconnected.