Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Yep. Amazing that we both had the EXACT same issue. Wonder if we should make Westinghouse aware of it, it has to be some sort of weakest link in the system.
I apologize, but did not get the voltage readings on the MOSFETs before I closed it up. I hope to get on that in the next day or two.
Thanks again for everyone's input! Hopefully this can walk someone else through another expected issue with this inverter board.
Collin
mobaar
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Last Activity: 07-06-2010, 12:04 PM
Joined: 03-02-2009
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Holy crap....it worked.
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Strange readings...
Some of the time the jumper gave me readings of 0, but other times it would read exactly .375V (or .4V or .38V, depending on the setting of the MM). Continuity of the fuse was nonexistant.
So if that proves that the problem is with that fuse...how in the world do I get one of those little things??? And how do I replace it? sheesh!
CollinLeave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Right. Where *exactly* is GND? I've heard too many conflicting cases of where exactly that black probe is going. Sorry, it's really a very basic question.
CollinLeave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
I am more than willing to look into this fuse issue like you are suggesting, but I have 2 very very elementary questions to ask (remember, I am new at this whole circuit board stuff!)
1.) I have my multimeter and I'm ready to take some DC readings with it. Red probe on the jumper in question, black probe where? Supposed to go to ground, but I want to make sure I'm doing everything exactly right before I go probing around on the PCB.
2.) How do I know if a circuit board fuse is "open?"...Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Well the CCFL inverter IC is a BIT3713, a 16-pin IC. Trying to find the datasheet on it now.
CollinLeave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Ugh, I'm finished but no dice on the backlight working.
I've checked and double-checked capacitor polarity, made sure there weren't any shorts in the system or any solder crossover, but it's behaving exactly like it did last time.
The MOSFET replacements checked out on a multimeter before I put them in, and it looks like everything is squared away. When I turn the monitor on, the backlight doesn't turn on; on the bright side (so to speak) there don't appear to be any overheating or shorting...Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Thanks to everyone for their input; the order to Mouser has been made. Keep your fingers crossed.
I have the replacement MOSFETs coming in either today or tomorrow. I have to think of a good way to get those things in without burning the board or the MOSFETs themselves. Probably will try to use an alligator clip when soldering leads into place.
Anyone care to speculate on whether I should test the board after new MOSFETs are in place or should I wait for the recap job before plugging anything...Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Alright, here is what I have planned in my cart now:
Mouser #: 647-UPW1E102MHD
Mfr. #: UPW1E102MHD
Desc.: Low Impedance Radial Aluminum Electrolytic Capacitors - 105Degree 1000uF 25V 105c 12.5x20 20% 5LS
Mouser #: 647-UHD1A222MHD
Mfr. #: UHD1A222MHD
Desc.: Low Impedance Aluminum Electrolytic Capacitors - 105 Degree 2200uF 10V 105c 12.5x20 20% 5LS
Mouser #: 661-ELXZ500ELL470MFB
Mfr. #: ELXZ500ELL470MFB5D
Desc.: Radial...Last edited by mobaar; 03-03-2009, 11:24 PM.Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Thanks for all of your responses. Regarding which capacitors to get, would the HE series of Nichicon be appropriate? It's the only line I could find for every capacitor (I think the 50V only had PV). I don't know the first thing about ESR so any help would be appreciated.
I think I'll hold off on replacing the big-boy capacitor per your suggestions. It looks good, and although I had to cut through the thermal paste to get a look at the other side of the capacitor, everything looks A-OK so I'll hold off...Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Updating with the 2-letter code:
3x 25V 220μF (KF)
2x 25V 1000μF (KF)
1x 10V 2200μF (KF)
1x 10V 1000μF (KF)
1x 50V 47μF (GL)
1x 50V 22μF (GL)
1x 400V 100μF (KM)
This is all still pretty new to me. I know low ESR is where I want to go, and I even see the parts list for Nichicon high-to-low ESR, I just didn't find my particular caps listed...maybe that's because they were too high of ESR. I'll do some more searching
CollinLeave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Thanks, Eduardo. I'm calling it a night for tonight so we'll see what develops tomorrow morning. I'll keep the shopping cart open so I can pick up where I left off tonight.
Thanks again!
CollinLeave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Ok, here is what I've put together at Mouser:
Mouser #: 647-UPTW6101MHD
Mfr. #: UPTW6101MHD
Desc.: Low Impedance Aluminum Electrolytic Capacitors - 105 Degree 100uF 420V 18X35.5 20%
Mouser #: 647-UVZ1H220MDD
Mfr. #: UVZ1H220MDD
Desc.: Radial Aluminum Electrolytic Capacitors - 105 Degree 22uF 50V 105c 5x11 20% 2LS
Mouser #: 647-UVZ1H470MED
Mfr. #: UVZ1H470MED
Desc.: Radial Aluminum Electrolytic Capacitors - 105 Degree...Leave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Well, at this point it's looking like I'll probably just order some Nichicon capacitors from Mouser. Maybe it's best to share what I'm thinking of getting and getting your feedback? I just don't want to be "that person" that is asking obvious questions that are answered in the FAQ, which I'm still reading through to make sure I'm not being redundant.
CollinLeave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Thanks all for your help! I will post to you guys with results...now to find some capacitors...
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
For the capacitors, here's what I see:
CapXon:
3x 25V 220μF
2x 25V 1000μF
1x 10V 2200μF
1x 10V 1000μF
1x 50V 47μF
1x 50V 22μF
They're all CapXon but the big guy is turned so I cannot see it and the heatsink material is holding it down.
CollinLeave a comment:
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Re: Issue with Westinghouse 19" LCD Monitor (large pics)
Well I found these 2 MOSFETs on eBay for $8 shipped, with the 40T03 specification:
[url]http://cgi.ebay.com/LOT-OF-(2)-TWO-40T03GP-POWER-Mosfet-DAC-19M005_W0QQitemZ370166175275QQcmdZViewItemQQimsxZ20090228?IMSfp=TL090228189007r3997[/url]
Would those work? Maybe with that I'd only need to replace 1?
How about the other problem....is there an easy way to see if there are any additional issues?
Thanks!
CollinRe: Issue with Westinghouse 19" LCDLeave a comment:
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Issue with Westinghouse 19" LCD Monitor (large pics)
Hi all,
I actually came upon this website quite by accident. As it turned out, I came here by doing a Google search for a particular part (to be explained below) and lo and behold, I think I may have found the place that might save me a headache, two arms, and perhaps a portion of my leg.
So here's the issue:
I have a Westinghouse L1975NW 19" LCD monitor...well, it's actually a nonworking one. One day I came into my office to find the screen blank, which typically does not bother me since I use suspend, but when I tried to startup the computer,...Last edited by mobaar; 03-02-2009, 05:53 PM.
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