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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Westinghouse W32701 - Display problem

 
 


Fred77
Novice

Apr 22, 2008, 9:31 PM

Post #1 of 10 (204 views)
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Westinghouse W32701 - Display problem Can't Post
I have a Westinghosue W32701 LCD.

When I turn the LCD on, I get the blue input screen which flashes very quickly, just long enough to see the input channel text, and then the display shuts off.

The unit is staying powered on after this, and the audio is still working.

Does anyone have an idea of where to begin checking to possibly determine the problem?

Thanks



techchris
Veteran

Apr 23, 2008, 8:17 AM

Post #2 of 10 (193 views)
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Re: [Fred77] Westinghouse W32701 - Display problem [In reply to] Can't Post
first thing is to look and see if the back lights are staying on or going off.you may have to take off the back and look through a hole in the chaassis somewhere.


Fred77
Novice

Apr 23, 2008, 9:32 AM

Post #3 of 10 (190 views)
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Re: [techchris] Westinghouse W32701 - Display problem [In reply to] Can't Post
I am getting ready to take it into a dark room and check for this, but I believe I already know the answer.

Ok, since I can see the blue screen for about 3/4 of a second, I know the backlight is on for that period. After the screen shuts off, I can tell by the black color of the screen that the backlight is in fact NOT remaining on.

The TV is still powered on and functional it appears, because the source button works. If I press the source button enough times to make it through a complete cycle of inputs, I get the blue screen flash again very quickly.

Can you tell me, if it was a problem with the backlight, would the backlight even be coming on for the split second which it does? Because I would assume that if the backlight was bad, there would simply be nothing displayed ever.


techchris
Veteran

Apr 23, 2008, 10:18 AM

Post #4 of 10 (185 views)
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Re: [Fred77] Westinghouse W32701 - Display problem [In reply to] Can't Post
the lights are like 1960's tube lamps people had in kitchens.either the starter was faulty or the tube itself,either way the light would flicker and try to startup but failed. so my guess is the inverter board is faulty or worse case scenario the screen is faulty as the backlights are built into the screen.


Fred77
Novice

Apr 23, 2008, 5:33 PM

Post #5 of 10 (176 views)
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Re: [techchris] Westinghouse W32701 - Display problem [In reply to] Can't Post
I honestly do not think the backlight is faulty. The screen seems to be starting very consistently, and looks like a normal blue for that instant I can see it. It is not flickering or flashing differently each time, like an erratic old light.

It seems the problem lies deeper, in that something is not getting the signal across the board and onto the display. Some sort of circuitry must be sensing the error and flipping the display off.

Is there any means a technician uses to diagnose such problems, or do they themselves simply use a crude means of guessing like we are doing?

I realize each model has specific circuitry and no two are equally diagnosed, but man, somehow I must be able to diagnose this thing. I really can't afford a new LCD right now, as bad as that may sound.

How could I actually test the components, such as the back lights, for proper operation?


techchris
Veteran

Apr 24, 2008, 5:00 AM

Post #6 of 10 (169 views)
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Re: [Fred77] Westinghouse W32701 - Display problem [In reply to] Can't Post
you have not said if the back lights are on or off when you have no picture.till we have established this then we can go no further.


Fred77
Novice

Apr 25, 2008, 12:05 AM

Post #7 of 10 (163 views)
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Re: [techchris] Westinghouse W32701 - Display problem [In reply to] Can't Post
They are turning off when the screen shuts down.

I don't know anything about repairing LCDs, but it just seems the problem is oriented somewhere outside of the screen to me.

But, just in case, is there some way which I could remove the backlight, and power the backlight on externally to check its continuous operation?

I just need some means of limiting the variables which may be involved.


(This post was edited by Fred77 on Apr 25, 2008, 12:06 AM)


techchris
Veteran

Apr 25, 2008, 3:27 AM

Post #8 of 10 (156 views)
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Re: [Fred77] Westinghouse W32701 - Display problem [In reply to] Can't Post
then your problem is either the inverter or the screen itself.you can only check by substitution,a costly way of doing things but most flat screens have no individual parts available,only complete boards,which is why most end up as landfill due to the cost.


Fred77
Novice

Apr 25, 2008, 9:05 AM

Post #9 of 10 (152 views)
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Re: [techchris] Westinghouse W32701 - Display problem [In reply to] Can't Post
What about using a volt meter to check the inverter? Is there an easy way of doing this? Thanks


Fred77
Novice

Apr 25, 2008, 12:58 PM

Post #10 of 10 (148 views)
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Re: [Fred77] Westinghouse W32701 - Display problem [In reply to] Can't Post
Ok, I tested the leads coming in on the board from the 12V 150w inverter.

I'm getting 11.88v dropping to 11.84v when the screen flashes on quickly. I know, it doesn't really say a whole lot. But it sounds like the inverter is working alright.

I don't think I could really check amperage because the only load going would be the speakers.

 
 
 


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