visio vx37l with black screen no sound

[bobbyg]

Hi,
I'm new to this forum and hope I can get some help in solving this problem.
Heres where I'm at. Several weeks ago while watching this 2.5 year old visio hdtv, the screen went black and sound quit, and lost all controls. Had to unplug to turn off. After plugging it back in and power on, with remote, the visio light goes from orange to white, then back to orange. I pulled the set appart and tested the power supply voltages. I had no 24vdc, an found a tiny resistor blown. Their were also no visible bad caps or discolorations on it or any other board. So Being an impulsive guy, I immediately ordered a new power supply. I quickly installed it and excitedly turned it on. Well, the orange light came on. I pushed the power on button and the orange light turned white, but still no light or sound. Then i started checking voltages again. Heres what I have found so far.

Main Board 3637-0112-0150
f1---12vdc
f2--- 5vdc
u33--3.29vdc
u2---3.29vdc
u3---0vdc
u4---3.29vdc
u7---1.08vdc
u8---3.3vdc
u9---1.51vdc
u10--2.59vdc

New Power supply 24vdc,12vdc,5vdc

Note: Does u3,u7,u9 and u10 have a problem with the lower voltages, if so what should they be. Is there something else I should check or am I wasting my time and money. Bobbyg

[ben7]

Re: visio vx37l with black screen no sound

Hi,
I'm new to this forum and hope I can get some help in solving this problem.
Heres where I'm at. Several weeks ago while watching this 2.5 year old visio hdtv, the screen went black and sound quit, and lost all controls. Had to unplug to turn off. After plugging it back in and power on, with remote, the visio light goes from orange to white, then back to orange. I pulled the set appart and tested the power supply voltages. I had no 24vdc, an found a tiny resistor blown. Their were also no visible bad caps or discolorations on it or any other board. So Being an impulsive guy, I immediately ordered a new power supply. I quickly installed it and excitedly turned it on. Well, the orange light came on. I pushed the power on button and the orange light turned white, but still no light or sound. Then i started checking voltages again. Heres what I have found so far.

Main Board 3637-0112-0150
f1---12vdc
f2--- 5vdc
u33--3.29vdc
u2---3.29vdc
u3---0vdc
u4---3.29vdc
u7---1.08vdc
u8---3.3vdc
u9---1.51vdc
u10--2.59vdc

New Power supply 24vdc,12vdc,5vdc

Note: Does u3,u7,u9 and u10 have a problem with the lower voltages, if so what should they be. Is there something else I should check or am I wasting my time and money. Bobbyg

Sounds like the main processing board.
But, is it a LCD or a Plasma TV?

Maybe a short circuit caused the resistor to burn out on your old power supply.

-Ben

[bobbyg]

Re: visio vx37l with black screen no sound

Sorry about that, Its an lcd vx37lhdtv10a Bob

[bobbyg]

Re: visio vx37l with black screen no sound

Ben,
I understand the inverter board needs 24vdc and a back light on signal tcontrol signal to turn on the back lights, I have the 24vdc at the inverter fuse, how do determine if I have the back light on signal using a digital voltmeter? I'd like to rule out the inverter if I can, before I get a main board.

[BarrelRoll]

Re: visio vx37l with black screen no sound

I have the same set with the same problem. Logo is orange, power up it goes white with the backlight coming on. Nothing on screen and can't turn it off.

Power supply is putting out all the correct voltages, the backlight fires up but then I can't turn the TV off and nothing comes on the display. Also the optical audio output does not light up the laser diode.

Checked F1 and F2 and both are OK. Getting 5 volts at the 7805T. It would not be unusual to see a 1.0 to 1.5 volt level for the ARM CPU core, but I suspect that the voltages that are near 3.3v, but not quite are a problem, and the 0 volt probe you have.

This is apparently a pretty common problem and I'd rather not spend ~$100 on a replacement mainboard if it's a bad cap or failed solid state relay or something like that. None of my caps are showing any signs of damage either, though I think they are all Taicon. It's like the set can't get out of standby to actually boot and turn on anything but the backlight. It seems to be a fairly common problem but nobody has turned up what the problem is yet.

[PlainBill]

Re: visio vx37l with black screen no sound

You'd get more help if you had posted this in the proper section. It belongs in the 'Electronics Theory and Troubleshooting'; 'Troubleshooting TVs and Video Sources' area. I suggest asking a mod to move it.

PlainBill

[ratdude747]

Re: visio vx37l with black screen no sound

You'd get more help if you had posted this in the proper section. It belongs in the 'Electronics Theory and Troubleshooting'; 'Troubleshooting TVs and Video Sources' area. I suggest asking a mod to move it.

PlainBill

Been busy with college, missed this. Shame on me, the FAQ janitor!

thread moved.

(a lot of bad backlighted vizios lately... vizio?)