Re: Vizio V042L FHDTV10A No Video but has sound

Ok, so I got it working again, the problem was with the built in regulator on the driver IC. I noticed it was floating ~1VDC instead of the 5VDC. It was a simple chip replacement and the TV booted right up. Thanks for all your help everyone.

Re: Vizio V042L FHDTV10A No Video but has sound

I shall do just that, I wanted to use the good board to confirm my findings. Which it did. The master board however still exhibits the same behavior that it did in the tv, namely it turns itself off after about a second. Any ideas as to why that would be? I dont want to replace all of the chips on the slave only to have the problem still exist.

Re: Vizio V042L FHDTV10A No Video but has sound

I've got both of the inverter boards in the lab today and I'm planning on powering them both up using a bench supply. Im going to assume that the flex cable supplied the PWM control for the CCFL brightness so i'll need to mock that up as well. The goal is to see if the driver IC is actually driving the MOSFET's correctly and to do a comparison between the master and slave circuits. I did notice last night, however, that when i was tinkering around with the master inverter that the only time it worked was when i had the chassis ground...

Re: Vizio V042L FHDTV10A No Video but has sound

I did check the master board as well. That was what i used for a baseline value :-). The resistance values of the master board are as follows:
Q1 Q2 Q3 Q4
1 to 2 285K 290K 280k 292k
1 to 3 284K 298K 280k 280k
2 to 3 8.49K 8.5K 8.5K 8.5K

Re: Vizio V042L FHDTV10A No Video but has sound

Ok, I've taken the tv apart and im pretty sure that its the slave inverter board. I've confirmed that the power supply is functioning normally (5V standby on all the time and 24 VDC to both inverters when powered on), the master inverter has a blue LED that lights up when the power button is pressed and you can see the backlight turn on on the master side. The slave side does not turn on. I've confirmed power is being received, I cant locate the LDO for housekeeping supplies but the test points show 5.047V and 3.748V when measured...

Re: Vizio V042L FHDTV10A No Video but has sound

Wow, glad I got that pointed out to me, thanks.

Re: Vizio V042L FHDTV10A No Video but has sound

I tried using internet explorer 8, to no avail unfortunately. Is there anyway someone could upload it for me? I've attached a picture of the loaded website as well just so you can make sure I'm not being a moron or something. I'm going to disassemble it in a couple of hours and take a look at the boards, I'll make sure upload correct pictures of the inverter boards as well as resistance measurements of the MOSFET's...

Re: New Members - please post your introductions here

Hi,

My name is Mike, I'm 25 years old. I graduated from Marquette University with a BS in Computer and Electrical Engineering. I'm currently working as a hardware design engineer for a company that designs cockpit upgrades for aircraft displays.

Hi,

New to the forum so any help you can provide would be great. I have a the TV listed in the description and it started acting up. I power it on and video shows up for a second or so before turning off. The right side of the TV has normal video which then seems to fade to black on the left side of the TV. This leads me to believe that one of the inverter boards is damaged. I've been looking for schematics and service manuals however I cant seem to find any for this model, and doesnt have a download link on the page. Again any help would be greatly appreciated.