Vizio E480i-B2

[imraneesa]

Hi all
I am trying to troubleshoot the above mentioned tv power supply board. The pwm ic Ld7913 was bad and I changed it. Also R915 was open and one zener diode was short.

There is one diode in the secondary section for standby 5v was short also.

After replacing all bad parts now I am only getting 1.75v on vcc pin of pwm ic. Any help will be highly appreciated. Thank you. There is also another ic that detects AC i guess IN1s101.

[dskall]

Re: Vizio E480i-B2

LD7913 shows as a mosfet. What pwm are you talking about?

[imraneesa]

Re: Vizio E480i-B2

LD7913 shows as a mosfet. What pwm are you talking about?

Ld7913JGM6 is 5 pin Ic

[imraneesa]

Re: Vizio E480i-B2

Here is the picture of ic

[lotas]

Re: Vizio E480i-B2

Try also replacing the optocoupler (817) and adjustable zener diode (431).

[imraneesa]

Re: Vizio E480i-B2

Try also replacing the optocoupler (817) and adjustable zener diode (431).

I changed optocoupler. I forgot to mention. But even though these two parts are bad shouldn't there be good vcc on pwm ic?

[dskall]

Re: Vizio E480i-B2

Can't find datasheet. I assume it gets it's initial voltage off main input. Then off of primary winding to supply run voltage. Need to check the diode and capacitor on vcc.
RJ would be the go-to guy on this.

[imraneesa]

Re: Vizio E480i-B2

Can't find datasheet. I assume it gets it's initial voltage off main input. Then off of primary winding to supply run voltage. Need to check the diode and capacitor on vcc.
RJ would be the go-to guy on this.

I hope RJ get some chance to help in troubleshooting this problem.