Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
I think it is both the transformer number 3, AND the power supply being unstable under load.
I will retest with an 18v battery configuration tomorrow, as I don't have access to a power adapter, I'll hook a 6 volt and 12 volt car battery in series and use that to power the monitor. 18v should be close enough to 19v to work.
If it is only the transformer, the other lights should power on and stay on at least, except for the lights powered by the possibly faulty transformer.
I will let you know...
gregory121295
Member
Last Activity: 05-26-2016, 10:54 PM
Joined: 06-19-2012
Location: Freehold, NJ
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
It is difficult to follow the traces of Xfmr 3, but I did an odd little test. After switching the board around, so that the plugs are reversed and the transformers now power different bulbs in reverse order, all of the lights flickered on at full power for about a second before shutting off. Also, I re-tested Xfmr 3 and got 634 ohms, versus the 612 ohms average of the other Xfmrs.
After I follow the traces, I will let you know about Xfmr 3, but I think you were on to something.Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
The power supply is external, and it outputs 19 volts and 3.42 amps.
There are 6 seperate 'U' tubes that light up.
The power input from the plugs is split among the 6 tubes.
Each plug has 8 pins, 4 sets of positive and negative. Each plug can power up to 4 separate lamps.
The plug more away from the center powers ONLY the two lamps on it's end, with 2 sets of wasted pins that are not connected to anything.
The other plug towards the center powers the remaining 4...Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
When I start the monitor, only RIGHT after i plug in the power to the wall the lamps kind of flicker on for a second or two. Rather than explain it, here's a video of it.
[URL="http://youtu.be/Bnc4FkGyy2w"]http://youtu.be/Bnc4FkGyy2w[/URL]
EDIT: I managed to remove the light assembly. here's a picture of both sides of the circuit board.Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
When I start the monitor, only RIGHT after i plug in the power to the wall the lamps kind of flicker on...Last edited by gregory121295; 06-21-2012, 01:48 PM.Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
Here's pics of how the lights plug in. Working on readings from the xfmrs now.
Edit:
Here are the Xfmr readings. I'm getting a lot of no readings though. Any idea why?
Xfmr 1:
x+a= 610 ohms
x+b= no reading? (stays on "1" even if I go up to 2000k)
x+c= no reading?
x+d= no reading?
X+e= no reading?
x+f= no reading?
x+g= no reading?
y+a= 610 ohms
y+b= no reading?
y+c= no reading?
y+d= no reading?
y+e= no reading?...Last edited by gregory121295; 06-21-2012, 08:42 AM.Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
Rtech, the lamps plug into the black plugs on the bottom of the board, as shown in this photo.
yes, I have neg in com and am taking measurements with the circuit off....Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
Yes, it turns out they are mosfets. U2, however, is 20 pins, and I can't find the datasheet for it. Should I test both channels, and how so? I can't seem to get a reading at all with my multimeter set to 200 ohms and my negative lead in com. The meter just says 1, as if nothing is connected.
Here's a schematic of the mosfet, TPC8401.
EDIT:
Rtech, did I test the right pins? Which pins are the secondary windings? Should my negative lead be in com or 10adc? I figured com, but I get a much higher...Last edited by gregory121295; 06-20-2012, 08:01 PM.Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
Here's a pic of both the top and bottom of the actual board. Sorry for the quality, I'll upload better photos soon....Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
Ok. Here's a diagram of the transformers, with measurements of the secondary windings. I can also measure the primary windings if need be.
Xfmr 1:
x + y = 0.4 ohms
x + z = 0.4 ohms
y + z = 0.4 ohms
Xfmr 2:
x + y = 0.4 ohms
x + z = 0.4 ohms
y + z = 0.4 ohms
Xfmr 3:
x + y = 0.4 ohms
x + z = 0.4 ohms
y + z = 0.4 ohms
Xfmr 4:
x + y = 0.4 ohms
x + z = 0.4 ohms
y + z = 0.5 ohms
EDIT:
I should add...Last edited by gregory121295; 06-20-2012, 09:25 AM.Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
yes. Underneath the board, there are two black plugs, spaced about 2 inches apart. Each plug has two slightly separate sections of four holes.Leave a comment:
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Re: Westinghouse lcm-19v1 sl 2 Seconds to Black
Right now, I don't have access to a camera, so It's a stock photo. I'll add actual pics sometime soon.Leave a comment:
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Westinghouse lcm-19v1 sl 2 Seconds to Black
So, I have a monitor that I've had for a couple months. I used it for about a week a month ago. It started out with the back-light working but the monitor needing to be hard reset until the back-light would stay on. After the back-light was on for a couple minutes, sometimes it would turn off later, sometimes it wouldn't.
I didn't think anything of it until one day, after about a week, it finally just turned off. I know it's the backlight, as the panel works just fine.
What the odd thing is, though, is that the only non surface mount capacitors on this board are on...
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