Olevia 532-B12 32" LCD Flickering backlight no picture

[1997eclipsegst]

Hey everyone,

Working on a Olevia 532-B12 32" LCD

Try to power on and the backlight flickers for 10 seconds the shuts off. Tried to look at the screen with a flashlight but doesn't display a picture.

It has a Phillips/LG panel and inverters
Panel # LC320W01
Inverter #'s KLS-EE32C1-M and KLS-EE32C1-S
Tested the fuses on both inverters and are good. I get a steady 24.5vdc on the connectors going to the inverters while the backlight is flickering and when the backlights shut off I get 25vdc until the set is shut off.
There is a led on the master that will come on when the set is turned on then slowly fade out.

Power supply # Arestech AEP013
Nothing on the power supply to show what the pinouts are but was able to read the 24vdc going to the inverters on plug CN902 and 12vdc and 5vdc going to the main board from plugs CN903 and CN904.

Checked the fuse on the T-Con and is good and reads 12vdc while the set is on.

Here is the strange part. When I disconnect the small 4 pin ribbon that goes from the master inverter to the T-Con and power on the set the backlights will come on steady for 3 seconds, shut off for 10 seconds, turn on for 3 seconds, then shut off and never come back on until the set is shut off and turned back on.

Any thoughts?

[tom66]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

Check and see if BLON is steady.

[1997eclipsegst]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

There is nothing labeled on any of the boards in this set. Tried looking for a service manual and can't find one.

What I do see is what appears to be some type of control wires from the main board to the master inverter. When I test these I get 3.5vdc for the first 10 seconds and then drops to 1.5vdc. The 3.5vdc stays steady while the backlight flickers and shuts off. There is a plug for these 2 wires half way between the main board and inverter. When unplugged I get out of the main board 5vdc for 10 seconds and drops to 2.5vdc

[tom66]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

That seems about right. High brightness when powered up and dim down when no signal detected, to save power. See if plugging in a working input makes that go up.

[1997eclipsegst]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

I have tried multiple inputs (Coax, VGA, Composite, HDMI) and doesn't change. Not knowing exactly how to change the source I have tried just pressing the source button multiple times and pressing the source button once and using the channel up and down arrows with no change either way. I don't get any sound except for a very faint hiss and doesn't change if I turn the volume up or down.

Does it sound like the main board might be bad?

[tom66]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

It's probably not a bad main board; it could be just a backlight setting that's set low. More likely bad inverter or bulb. Please check the part# for the main controller chip. Also, have you tested the transformers and FETs? Bad slave could cause flickering backlight.

[1997eclipsegst]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

Would the backlight problem keep it from producing sound or picture? Should I be able to see some type of image using a flashlight on the screen? I will do some more testing and report back a little later.

[tom66]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

Some LCD panels don't work well with seeing an image with no backlight due to the front diffuser. So no backlight may mean no visible image. As for no sound, I have been fooled by this before. I had a TV with no backlight and the user said sound stopped after a few days. Found out the user had muted the sound (perhaps fiddling with buttons trying to get it work?), and that when pressing the source button the TV didn't switch between sources but instead brought up a menu to select them using the D-pad on the remote... so no amount of fiddling there would make it work.

[1997eclipsegst]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

Thanks Tom, That makes sense. Could be a combination of both of those with this one.

[1997eclipsegst]

Re: Olevia 532-B12 32" LCD Flickering backlight no picture

Just wanted to update this.

I had a chance to pull the inverters and check them over. What I found was alot of corrosion on the copper grounding pads and test points. These were the only boards that had this, the rest looked fine. I sanded the corrosion off to see how much damage the corrosion caused and a couple of spots looked completely eaten away and not connected.

I installed a set of replacement inverters I picked up and upon powering up the backlighting would still flicker but would never shut off like it did before. I unplugged the T-Con next and upon powering up the backlighting would stay on with no flickering and did not shut down like before. Still no picture either way.

Decided to take a chance and picked up a replacement T-Con. Swapped it in and powered it up and have picture now. Played around in the menu and found the internal speakers were shut off so that explained no sound.

Put everything back together and has been working great!