Once again a Visio VX42L - No Snd or Pic

[boeing711]

Cheers all… Was hoping to gather enough information so as not to have to bother the forum with another repetition of a similar Visio problem…. No luck!! Pulling the back off the set, grabbing a screw driver and Multimeter and diving in is like christmas for me....

Issue: Visio VX42L has no display, back light or sound. When plugged in, Amber "Visio" is present and turns white when turned on by either the switch or remote. *** "VISIO" returns to amber when turned off by sw or rmt.

Trouble shooting thus far - Closely checked ALL caps on main, inverter and power boards. All looked good.
Checked pwr board - 5vsb(stby pwr), 3.0v PSON, 12V and two 24Vdc all available with power applied.
Fuses - F1 and F2(main brd),inverter and pwrsupply read .000, There's mention of a fuse on the TCon... but I can't find it?
Voltages at the regulators all look good, (triple checked hoping U33 was bad...NOT!!)
U33 - 3.30
U2 - 3.32
U7 - 1.28
U8 - 3.28
U9 - 1.52

Any help or guidance as to what direction I can take now is greatly appreciated...

[budm]

Re: Once again a Visio VX42L - No Snd or Pic

Are you getting BL_ON signal at the inverter board connector? Can I get good closed up pictures of the areas around the inverter connectors. Fuses on the inverter are good? is the Inverter board has a name DARFON or Che-mei on it?

[Mr Bill]

Re: Once again a Visio VX42L - No Snd or Pic

Here is where the fuse is on the tcon. So the "vizio" logo goes from orange to white and the tv can be turned off with the remote or keyboard?

[retiredcaps]

Re: Once again a Visio VX42L - No Snd or Pic

Voltages at the regulators all look good, (triple checked hoping U33 was bad...NOT!!)
U33 - 3.30
U2 - 3.32
U7 - 1.28
U8 - 3.28
U9 - 1.52

The readings themselves may or may not be correct depending on the voltage regulator part number and its relationship to the other pins.

Report them like so along with the part number (include all lines on the IC) of the IC.

U100
AS1117-33
pin 1 = 0.0
pin 2 = 3.3
pin 3 = 5.0

[selldoor]

Re: Once again a Visio VX42L - No Snd or Pic

When you say No sound does the source have sound? dvd? n.b. last user may have had sound muted. Was the set yours - do you know what it was doing prior to going off- flickering - power surge -gaming
Based on what you have said so far reseating cleaning and replacement of all cables
should have been the first "test".
Straight on pics ,without flash, are best for troubleshooting - can you do the inverter board -probably in 3 sections. (Are there two fuses on it)
Can you see a very dark image on the screen -try a flashlight at various angles.

[bigdozer]

Re: Once again a Visio VX42L - No Snd or Pic

I've got the same tv with the same problem. I originally thought the mainboard was bad but all my voltages were good on the regulators. So i suspected the tcon. Ordered a new/used one and have the same problem. If i unplug the two left ribbon cables the tv powers up fine and half the screen works with audio. Hdmi, component, and composite work. If i unplug the right two and leave the left ones plugged in it doesn't work. It's confused the hell out of me so i gave up for a while. This thing is in mint condition too. All the other posts i've seen on this model had seperate master and slave inverters. Mine too has the one inverter board on the left. Guess i'll have to plug it up and take some measurements to compare.

Checking my thread on this tv apparently i replaced u7 and u33. I pulled them from the working mainboard of vx32l that had a busted screen. Its definately been awhile since ive messed with this thing.

[boeing711]

Re: Once again a Visio VX42L - No Snd or Pic

Thanks up front for the replies...
budm... BL_ON signal is new to me. I'm not noticing any king of signal at turn on around the INV pwr connectors. See img's for Inverter board pics. Name on board is "LOGAH"

Mr Bill... Thanks, reads .000 and yes turns off and on/off via keybrd and remote with corresponding logo color changes???

retiredcaps... As per ur request.

(pin 1/2/3)
U33 - 2.06/3.30/5.07 -> AMC1117 F0735T
U2 - 2.03/3.32/5.07 -> AMC1117 F0735T
U7 - 0.04/1.28/3.30 -> Same
U8 - 2.03/3.28/5.11 -> Same
U9 - 0.01/1.52/3.30 -> K1117S15 726

selldoor... My primary TV, new in 2008, died Nov2010, . Went to turn it on one morning and "nutin." No indications of any kind of surge. Connections were unplugged and reseated. It's been setting in the Study for a year and a half waiting for its resurection. Your comment about the sound prompted me to double check... "DUH ME!!!" I attached a DVD and HDMI component to the TV and had SOUND but NO picture of any kind. TV responds to the remote "TV input" and "vol" input changes. (SRY, should have verified before posting) I Cannot pick up any kind of picture on the screen. Yes, TWO fuses and both check .000.
Anyway.... I hope the new pics are acceptable.

[Mr Bill]

Re: Once again a Visio VX42L - No Snd or Pic

Did you try to disconnect the 2 left ribbons and see if you get half a screen and vice versa like bigdozer did?

[budm]

Re: Once again a Visio VX42L - No Snd or Pic

Did you check F1 on the inverter board? I think it is open.

[bigdozer]

Re: Once again a Visio VX42L - No Snd or Pic

I'm betting its the inverter. Try the flashlight test.

[boeing711]

Re: Once again a Visio VX42L - No Snd or Pic

Again thanks for the direction...

How do you guys find these little thingie's??? budm's is correct the F1 is open. Geeze... looked all over that area for an F anything.
Can't figure out how the pull the ribbon connectors from the TCon. A little worried about pulling ribbon loose.
Flashlight shoes no picture on screen.

So... I'm gonna have to replace the F1 fuse... the "20" would be ??

[budm]

Re: Once again a Visio VX42L - No Snd or Pic

Very common failure, most people think that part is a resistor. Try 1.5A fuse, just get regular fuse and solder it in place, or if you have 0.22 Ohm 1/4W you can use that for testing. That is why I asked if ALL the fuses on the inverter board has been checked. Good clear pictures always help, your pictures are good hi-res for me to track down that fuse.

[boeing711]

Re: Once again a Visio VX42L - No Snd or Pic


I'll follow up on this post as soon as I can get this changed out.
To all .... Thanks again!

[budm]

Re: Once again a Visio VX42L - No Snd or Pic

I believe that is the only problem you have.

[boeing711]

Re: Once again a Visio VX42L - No Snd or Pic

Forum Gent's...
Better late than never... Sorry guys for the lack of a follow up on my repair. I was out of country for awhile,(military), and just forgot to get back in here. Any way the problem was the F1 on the Inverter board, (see#9 from budm). I couldn't find a fuse to replace the bad one, it's rather small. I found it eaiser to just order a new VX42L mother board for $60/with free /shipping off ebay. Installed the new board and presto----"great picture!"
Kids have been watching it every day now with NO problems.
Every reply to my problem was helpful and kept me focused in the right direction...
This is a great forum....Thanks to all!!

[boeing711]

Re: Once again a Visio VX42L - No Snd or Pic

Plez let me correct my last post.... I did not replace the mother board... I replaced the INVERTER board. Got to work on the proof reading.