Westinghouse lcm-19v1 sl 2 Seconds to Black

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

"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."
That would be different than other monitors,normally if there is one fault in the Backlight circuit it affects all of them, and they switch off.

[gregory121295]

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 the results as soon as I conduct the test.

[gregory121295]

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.

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

Another thought is as follows - Assuming you are correct in how the wiring is done for the lamps,then Each pair of lamps is driven by one transformer !!,and therefore the set of pins that are not used MUST be connected to a transformer that is not being used ??so therefore if that is the case, then the transformer that you measured that was different from the rest,is that one being utilised to drive a pair of lamps or not ?? If it is then change it with the one that is not being used,and that should eliminate the transformer question one way or another.
Maybe the reason for the 4 transformers is that this is a standard build, and the board could drive in fact another two pair of lamps from the 4th transformer for perhaps a bigger Model in the same range ??
Now perhaps I might be able to get some sleep,as this came to me just as I lay down.Good night.

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

Ok,ref the Power Supply,and I assume the 19V and 3.42amps details are from the Power Supply Label ??? I still think you need to beg,steal or borrow,another Supply and try that,also was there any indication ref voltages and functions on the input/output plug to the other board ??
Also time is getting on and bed is calling,sorry, will catch up tomorrow am UK time.

[gregory121295]

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 lamps with ALL 4 sets of it's pins.

It's hard to see how this works without the circuit in your hands, but I'm 99.99% sure that's how it works.

[budm]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

OK, now I see the edited post showing the U shape tubes. When the lamps are that long, the firing and sustain voltage will have to be higher than typical shorter tubes.
I see something like a DC jack on the board.

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

Photo 3 in Post 20, shows the 'U'tube,so waiting for an answer ref the power supply,is it internal or external,suspect the latter, so although the Voltage may be ok using a meter,it may be below par when a load is applied.Also the Tfmr 3 could still be faulty, from the measurements taken.I still am at a loss how these lamps are wired, or indeed why they need so many for a 19" monitor.

[budm]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

I cannot tell by the pictures if the tube is the U shape type or not.
If ALL the tubes act the same, then it has to be something that is common to the circuits.

[selldoor]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

Just to check did you all go back and see the EDIT on previous page Pics & Video

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

Budm raises a point.....is this powered by an external Power Supply ????,and if so have you tried a different one ?/

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

The left side,would seem to have NO electrical connection,as that is where the bend of the tubes go,so that side is purely for holding the lamps in place ????/

[budm]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

So if I get this correctly, with the length of the lamp, it is half lit, the other end of the lamp is dark?
It sounds like the lamp return wires are not connected, that is why I want to see the left side of the lamp assembly to see the lamp return wire connections.
Or the power supply is not supplying the full power.

[selldoor]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

And by the way, none of the lamps flash for a second?

Yesterday 09:18 AM
gregory121295
Re: Westinghouse lcm-19v1 sl 2 Seconds to Black


EDIT:
I should add that the back-light flickers on for about a second when I turn on the monitor, although only half of the bulbs turn on, and they don't look like they're on at full power.

[gregory121295]

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.
http://youtu.be/Bnc4FkGyy2w

EDIT: I managed to remove the light assembly. here's a picture of both sides of the circuit board.

[budm]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

Can I see closed up pictures of the left side of the lamp assembly? I want to see how the end of the lamps are connected.
And by the way, none of the lamps flash for a second?

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

All we were trying to do was identify the secondarys, and you have done that,worry not about the rest.Transformer 3 looks a little high !! Normally members work to the 3% rule,ie if there is more than a 3% difference in the secondary resistance, then its likely that the transformer may well be faulty, so 3 would look marginal ,and MAYBE the problem.I see Qty 6 'U' shaped lamps, have no idea how they connect together,or even if they do,as I have never seen this set up, so hopefully someone has who will leap in and advise us both,a quick glance would assume that only 2 actually light ,do you see anything from the lamps when you try to start the Monitor and associated PC Signal ??
Also there is a 4 0r 8 pin connector on the edge of the Board ,is there anything written on the board,OR the one it plugs into to indicate what voltage/Function etc each of the pins have??

[gregory121295]

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?
y+f= no reading?
y+g= no reading?

z+a= 610 ohms
z+b= no reading?
z+c= no reading?
z+d= no reading?
z+e= no reading?
z+f= no reading?
z+g= no reading?

__________________________________________________ ______

Xfmr 2:
x+a= 607 ohms
z+b= no reading?
z+c= no reading?
z+d= no reading?
z+e= no reading?
z+f= no reading?
x+g= no reading?

y+a= 607 ohms
y+b= no reading?
y+c= no reading?
y+d= no reading?
y+e= no reading?
y+f= no reading?
y+g= no reading?

z+a= 607 ohms
z+b= no reading?
z+c= no reading?
z+d= no reading?
z+e= no reading?
z+f= no reading?
z+g= no reading?

__________________________________________________ ______

Xfmr 3:
x+a= 629 ohms
x+b= no reading?
x+c= no reading?
x+d= no reading?
X+e= no reading?
x+f= no reading?
x+g= no reading?

y+a= 629 ohms
y+b= no reading?
y+c= no reading?
y+d= no reading?
y+e= no reading?
y+f= no reading?
y+g= no reading?

z+a= 629 ohms
z+b= no reading?
z+c= no reading?
z+d= no reading?
z+e= no reading?
z+f= no reading?
z+g= no reading?

__________________________________________________ ______

Xfmr 4:
x+a= 606 ohms
x+b= no reading?
x+c= no reading?
x+d= no reading?
X+e= no reading?
x+f= no reading?
x+g= no reading?

y+a= 606 ohms
y+b= no reading?
y+c= no reading?
y+d= no reading?
y+e= no reading?
y+f= no reading?
y+g= no reading?

z+a= 606 ohms
z+b= no reading?
z+c= no reading?
z+d= no reading?
z+e= no reading?
z+f= no reading?
z+g= no reading?

[Rtech]

Re: Westinghouse lcm-19v1 sl 2 Seconds to Black

Well you learn constantly the Black plugs, I never even considered as plugs, what does the bit on the end of the Lamp cable look like ??first time I have seen these !!! Lets know what the tfmrs read.

[gregory121295]

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.