Lights go out on Westinghouse LCM-19v7

[Lumberjack777]

Re: Lights go out on Westinghouse LCM-19v7

Truely test the function of this inverter board, you have to use the SAME lamp connection as used in this monitor since the connectors on the left side of thee board are the hot side and the return side of the lamps are the two connector on the top of the board, if you use the typical lamp connector with two pin (one pin is hot and another pin is the return), it will not be valid test. Which means that you still can have lamp problem.

I agree and thank you budm. I used to hang out in this forum awhile back, and would chime in if I was absolutely sure of a way to fix a particular monitor. I can see you are a great asset to the team.
Retiredcaps is a nick I always watched and respected and would read his comments. And a couple others too. But I'm sorta concerned because I was looking to see what PlainBill had written lately. It appears he hasn't posted anything since 3/3/2012. Over 3 1/2 months ago! That really concerns me. Since he usually had several posts every day.
Does anybody know what happened to PlainBill. And if he's ok?

[budm]

Re: Lights go out on Westinghouse LCM-19v7

Truely test the function of this inverter board, you have to use the SAME lamp connection as used in this monitor since the connectors on the left side of thee board are the hot side and the return side of the lamps are the two connector on the top of the board, if you use the typical lamp connector with two pin (one pin is hot and another pin is the return), it will not be valid test. Which means that you still can have lamp problem.

[Lumberjack777]

Re: Lights go out on Westinghouse LCM-19v7

Ok, thanks Retiredcaps. I learned a lot from those bookmarks. And to think I just tossed out a few CFL bulbs. *facepalm* That's a really interesting testing method Bud came up with.
Ok, now it's getting curiouser and curiouser. As Alex points out a few posts earlier. The CCFL connectors are not normal with this monitor. It has 4 input (thick) wires together on 2 connectors. And the 4 return (thin) wires together on 2 connectors that connect to a completely different area on the power board.

If this thread ever come to the point, where it's suggested that known good CCFLs be substituted
The CCFL connectors are positioned different on this inverter, The 4 high voltage wires are on one side of the inverter, and the return wires are on another.

So I am testing the CCFL's with a similar fully functioning monitor. At first I tested the bulbs from the faulty monitor, to the good monitor, and they stayed lit. Then I tried your suggestion of connecting the bulbs from the good monitor to the socalled faulty inverter. And guess what? They stayed lit! Weird. I thought for sure they would go 2 seconds to black.
So here's my problem. How can I adjust the feedback circuit to not be so sensitive, and shut down so easily. And too allow the CCFL's to stay lit. Without compromising the safety feature of the feedback circuit. Thanks, L-J-7

[retiredcaps]

Re: Lights go out on Westinghouse LCM-19v7

Thank you for explaining how to calculate those voltages.

When I replied I was on my "downstairs" computer and didn't have all my bookmarks.

I wanted to add this from budm

https://www.badcaps.net/forum/showpo...4&postcount=65

I did test the CCFL's by plugging them into a similar monitor and they stayed lit.

I like doing the opposite. I use a known good ccfl and put it into the "suspect" lcd monitor.

More details starting with post #19 at

https://www.badcaps.net/forum/showthread.php?t=10419

Also, see budm's Inverter tester using old CFL

https://www.badcaps.net/forum/showthread.php?t=19987

[Lumberjack777]

Re: Lights go out on Westinghouse LCM-19v7

Interesting! Thank you for explaining how to calculate those voltages. I think what may have happened was that I bought a used or defective power/inverter board then. The power outputs to the logic board are good. But for some reason it turns on, then off. I did test the CCFL's by plugging them into a similar monitor and they stayed lit. I guess the problem is somewhere in the inverter. I'll see what I can find out and get back.

Thanks for all you do Retired

[retiredcaps]

Re: regulator voltages

That leaves the logic board as the possible culprit for this unusual (for me) 2 seconds to black.

Hmm, in 2+ years here, I have never seen the logic board as a root cause of 2 seconds to black.

I don't understand what the output is supposed to be. But I'll post the last 2 (U12 & U13)

Part number for both is EH11A 518BE
U12.....2.99, 4.24, 11.65
U13.....8.61, 9.88, 11.65

When there is no obvious part number that denotes a fixed output voltage, then it is an adjustable regulator. The "correct" output is usually pin 1 (adjustable) + 1.25v = output.

2.99 + 1.25 = 4.24 => good
8.61 + 1.25 = 9.86 => close enough to your reading of 9.88

[Lumberjack777]

Re: regulator voltages

This thread seems to be the closest to my problem. Same power/inverter board. Same logic board. Only this is for an Acer AL1914 Ab. Since the issue was never really resolved. I'm hoping maybe we can find a solution. The power/inverter board is new and works well. The CCFL's are tested good. That leaves the logic board as the possible culprit for this unusual (for me) 2 seconds to black. I'm quoting kingofcoins here; because my first 3 (U6, U8, U10) voltages are similar. But the reason his U10 & U12 did not have any output was because you need to have the input video attached. Pics are exactly the same as the ones posted earlier.

The logic REGULATOR datas...
U6....3.3V, 0.0V, 5.0 VDC part # BA33P 133CB
U8....0.0, 3.2, 5.0 VDC part # AMC 1117 33F0540FJ
U10...0.0, 2.0, 5.0 VDC part # AIC 1084-18PM 783CA
UI2....0.0, 0.0, 0.0 VDC EH11A 539BE
UI3....0.0, 0.0, 0.0 VDC EH11A 539BE

OK, my U10 had 1.79v in the middle leg. Retiredcaps mentioned that it needed to be around 1.80, so it's fine. I don't understand what the output is supposed to be. But I'll post the last 2 (U12 & U13)

Part number for both is EH11A 518BE
U12.....2.99, 4.24, 11.65
U13.....8.61, 9.88, 11.65

I'm not an expert with logic boards, or SMD voltage regulators. But maybe one of you understands. Is there a problem with U12 or U13? Thanks in advance. L-J-7

[alexanna]

Re: Lights go out on Westinghouse LCM-19v7

I hope these pictures are sufficient. Pictured are the replacement capacitors. The board reads:

DAC-19M001 BF
REV 02A

I'm still getting an image, but no backlighting.

If this thread ever come to the point, where it's suggested that known good CCFLs be substituted
The CCFL connectors are positioned different on this inverter, The 4 high voltage wires are on one side of the inverter, and the return wires are on another.

[alexanna]

Re: Lights go out on Westinghouse LCM-19v7

There is a hefty gray resistor on the right center side of the powersupply check it closley.

[retiredcaps]

Re: Lights go out on Westinghouse LCM-19v7

I'm still getting an image, but no backlighting.

Check the two green picofuses as suggested by jetadm123. A good fuse should read less than 1.0 ohms.

[lkvee]

Re: Lights go out on Westinghouse LCM-19v7

I hope these pictures are sufficient. Pictured are the replacement capacitors. The board reads:

DAC-19M001 BF
REV 02A

I'm still getting an image, but no backlighting.

[jetadm123]

Re: Lights go out on Westinghouse LCM-19v7

You'll need to post some good focused photos of the top and bottom of the entire power board, since there were several revisions of this board with each revision being slightly different.

1) If your board is similar to post #16, then check fuses F200 and F201 for continuity.

2) Check mosfets U200, U201, U202 and U203 for shorts.

[retiredcaps]

Re: Lights go out on Westinghouse LCM-19v7

I have the same monitor with an image but no backlight.

Check the fuses. A good fuse should measure less than 1.0 ohms.

Any thoughts on going forward with capacitors that are electronically compatible but physically incompatible?

As long as the uF, voltage, ripple, and ESR are similar (or better for ripple and ESR), larger physical size is fine as long as you can get the case back on without resorting to this ...

https://www.badcaps.net/forum/showpo...8&postcount=58

[lkvee]

Re: Lights go out on Westinghouse LCM-19v7

I have the same monitor with an image but no backlight. I saw two CapXon capacitors at 1000 uF and three at 220 uF with popped tops. I also replaced a third 1000 uF (@ 10V IIRC) which was flat, but also CapXon.

I didn't get a change in behavior. I still got an image with no backlight.

I'll look at the board again and proceed to replace any remaining CapXon capacitors.

I will read the previous articles in more detail, but I'd still love some advice on other parts to examine.

I have two Nichicon capacitors at 1000 uF and 25V, but they're wider and taller than the original Capxons. When I put them together, they want to form a V shape.

Any thoughts on going forward with capacitors that are electronically compatible but physically incompatible?

Thanks for reading!

[kingofcoins]

Re: parts for logic bard Westinghouse LCM-19v7

That U10 LDO regulator got pretty warm getting it out, and since it was 'out of spec' anyway want to put a new one in...and while I'm ordering at Digikey might as well have a U12,U13 as well....help with ordering these two parts,the nos shown below...

U10...0.0, 2.0, 5.0 VDC oem part # AIC 1084-18PM 783CA
UI2,U13....0.0, 0.0, 0.0 VDC " EH11A 539BE


Am I Ok for the U10... d/k # AP1084KLDICT-ND


And with this for U12... d/k # AP1117EGDICT-ND


Thanks for the help !

[retiredcaps]

Re: regulator readings

U12 and U13 read the same...about 25 ohms across 1st leg, 0.0 on middle leg then about 500 ohms across 3rd leg...I'm measuring from each leg to the other side of the regulator.

The "tab" at the top and pin 2 are usually the same. Hence the 0.0 ohms reading on the middle leg.

25 ohms suggests the regulator is shorted (bad). To verify, desolder both and retest out of circuit to ensure that the surrounding components are not affecting the measurement.

[kingofcoins]

Re: regulator readings

U12 and U13 read the same...about 25 ohms across 1st leg, 0.0 on middle leg then about 500 ohms across 3rd leg...I'm measuring from each leg to the other side of the regulator.

[retiredcaps]

Re: regulator voltages

The logic REGULATOR datas...
U6....3.3V, 0.0V, 5.0 VDC part # BA33P 133CB
U8....0.0, 3.2, 5.0 VDC part # AMC 1117 33F0540FJ
U10...0.0, 2.0, 5.0 VDC part # AIC 1084-18PM 783CA
UI2....0.0, 0.0, 0.0 VDC EH11A 539BE
UI3....0.0, 0.0, 0.0 VDC EH11A 539BE

According to PlainBill, low dropout (LDO) voltage regulators have a +/- 1% spec.

So U10 is out of spec. It should be 1.8V DC.

U12 and U13 should have voltages on it. In addition, I can't tell from the part number what the LDO output voltage should be.

For U12 and U13 test to see if these are shorted.

[kingofcoins]

Re: regulator voltages

The pico fuses F200, and F201 both measure about 0.5 +/- ohms.

BTW the readings out of the power to the logic are 3.2v, 5.0v, 20.0vdc

The logic REGULATOR datas...
U6....3.3V, 0.0V, 5.0 VDC part # BA33P 133CB
U8....0.0, 3.2, 5.0 VDC part # AMC 1117 33F0540FJ
U10...0.0, 2.0, 5.0 VDC part # AIC 1084-18PM 783CA
UI2....0.0, 0.0, 0.0 VDC EH11A 539BE
UI3....0.0, 0.0, 0.0 VDC EH11A 539BE

The middle leg of U10 is cut off.
The unit was lighting up for almost 2 seconds with that pzssit while I was running these checks, then back to amber.

[retiredcaps]

Re: Pics for the Westinghouse LCM-19v7

Let me know when we need bottoms too...

There are a number of voltage regulators on the logic board that you can test. List the part numbers and report the voltage on all pins for all them. U13, U6, U12, U8, and U10.

Not related at all, but on the power board, there are two green picofuses. Check to see if they are open or not.