Repair flickering Gateway FPD1830 flat panel LCD monitor

[SteveW]

This thread is for reader comments and questions about my article "How to repair flickering Gateway FPD 1830 flat panel color LCD monitor".

You can start a new thread, if you prefer.

[NameCaster]

Very nice article Steve. I found your site from your post on the site you credited in your article.
Thanks for taking the time to put this information together.

I do have one suggestion though and I'm sure you can relate to this as a programmer.
What is the function of a loop that does four of the same functions?
Well, in electronics its almost the same...scalability and flexibility play an important part of the development process.
Mind you, this can be a great approach but we all know its not the best.

To make a long story short, it's a lot easier to just eliminate all four 100uf capacitors and plop a 470uf in one set of the holes.
The only reason I would use a 470uf rather than a 400uf is 470uf is a common cap and the extra 70uf won't hurt a thing.
Cheers.
-Dave

[SteveW]

Hi NameCaster, and thank you for the information. Have you done the repair using a 470uF and does it work ok?

[Edit: I see from your posts at the other forum that you have done this successfully, more than once.]

I have almost no experience in circuit design, so on the few occasions where I have to do some tinkering, I try to stay as close as possible to the way it was originally done, even if I'm curious why they did it one way instead of some other way that seems simpler.

I do see that in both of the Moniserve (lcdpart) replacement inverter boards, they use 2 (presumably larger) capacitors instead of the 4 tiny ones.

Some of the questions that occurred to me while wondering why they used 4 x 100uf (and that I didn't know the answers to) were:

Was it just because they're small and fit in the available space? That seems fairly likely. On the replacement inverters, there's enough room to fold a big capacitor over on its side, but on the original Ambit board, it would be folded over a bunch of other components. Even if that poses no other problem, it would look ugly, and they wouldn't want that.

Or maybe they were super cheap? That seems likely, too, considering the result = widespread failure.

Or do they carry so much current that it takes 8 solder pads to handle it without overheating?

Or do 4 x 100uF have a different charge/discharge time than 1 x 470uF? I knew that at radio frequencies the capacitance value (and thus the charge/discharge time) affects the tuning of the circuit, but I had no idea whether this circuit has any requirement to operate at a particular frequency. So I didn't know if the difference between a 400 and a 470 would affect operation.

Thanks again!

[cazar86]

Hey Steve, thanx for the detailed walkthrough. So I followed your instructions on removing the inverter.. Luckily my brother had a soldering iron and was familiar with using it, because I was clueless.  We tried this with the 100 mfg 25v capacitors, they were slightly taller than the originals, but it worked great, good thing I didnt junk it.  So thanks again, you saved me over a hundred bucks.  Going to try this on my other sony lcd that went out about a year ago.

[SteveW]

cazar86, thank you for the report that it worked. I agree spending $3 plus some time is better than spending $100!

[leadlike]

Just happened to find about thirty of these monitors sitting out by the dumpster the other day.  Grabbed two and they both had this problem.  I did this fix for both of them in less than an hour.  To minimize heating the other components, I only used my soldering iron sparingly.  I pulled the caps off the board, and desoldered the old leads.  To prep for attaching the new caps, I drilled the holes clean from the back of the board.  If you drill from the top the soldering pads will be removed and that's no good.  A simple way to check your work is to do a continuity test across all of the +'s and -'s and recieve zero resistance, as these connections are in series to make the caps parallel.  Check that fuse on the board while you're there.  Very easy fix.

As for speculation as to why they used four 100 mikes, instead of a 470 could be that the 100's were plentiful and cheap, which these caps certainly are, or the specs for that inverter board called for it to be only such and such a depth and using four of these helped them meet that design goal.  If any of you experience failure after this repair, consider checking out the caps in the main power supply.

[SteveW]

Just happened to find about thirty of these monitors sitting out by the dumpster the other day. 

, what a find!! 

That's fantastic. If they're still there, you could make a small business repairing and selling them. Shipping charges on the monitors would be pretty high, but the inverters alone have been going for $35-45 on eBay for a long time. (Edit: looks like they're down to about $20 today.)

Also thanks for the additional information about drilling from the back and the continuity check and the power supply.

    
      
    

[gbjdocmd]

Thanks, Steve,
I just replaced my defunct FDP 1830 LCD Inverter, but when I started to replace the back monitor cover,
I found a fractured  Monitor Control Board which had been hanging free.
I'm afraid it had become wedged by the back cover during disassembly.
The part number is LG PN 6870T487C10.
I should have diconnected this and stored it in a safe place during my repair.
Also, some of the PFD graphics for repair, neglected to mention that 6 screws hold the back cover to the main frame.
They did not mention the 2 screws holding the base unit.
I have not found a source for replacing this board, but I am  waiting
for ICDParts.com.
Since this monitor has been heavily used for 4 years, I am replacing this with an Acer P19123 19" ACTIVE Matrix TFT LCD display. Prognosis for a final fix remains dim for the Gateway FPD 1830.
I hope this helps.
gbjdocmd

[SteveW]

Hello gbjdocmd! Welcome to the forum, and thank you for taking the time to post the additional information.

I'm guessing the Monitor Control Board must be the small board below the bottom of the screen, with the on/off switch and other buttons on it. As a general note, if I recall correctly, it has a strip of adhesive metallic tape connecting it to the main monitor chassis. It should normally be ok to leave the board hanging by its tape as you work (but you have to remember it's there); however, if it becomes necessary to remove the metallic tape, remember to retape it when you reassemble the unit. It probably acts as a grounding strap, equalizing any stray voltages between parts of the monitor or discharging static charges.

Alas, it's a lot easier if the base (which is just a heavy mechanical part and has no electrical connections to or from it) is removed first. 

It sounds like you're in somewhat the same situation I am, waiting maybe indefinitely for a needed part, while discovering that a 19" monitor (mine is a wide-screen 1440x900 pixels) is GREAT!  

As for the MCB, all you need is someone else's nonfunctional FPD1830 that they're throwing away. Maybe keep an eye on Craigslist in your area, or post a wanted notice. I keep meaning to do that, but in this sparsely populated region the probability that someone nearby is about to get rid of an FPD1830 at the same time I'm watching the classifieds isn't very high.

[rnearl]

after removing capacitors, i was able to open the holes easily using a small sewing needle, held in needlenose pliers and pushing the needle through the solder with a lot of force. it worked. i was unsuccessful in removing the solder, but this method worked to open the holes.

[SteveW]

Wow, that must have been a LOT of force. A sewing needle is much stronger and sharper than a straight pin. Good idea!

[rnearl]

steve
i replaced the 4 capacitors, but that did not fix it. by the way the ones you quote from radio shack are not high temp 105C only 85C. originals are 105C. don't know if that makes a difference, but i ordered exact replacement from parts express, copy and paste this url in your browser: ( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=020-1730 ), total cost, and i ordered 6, was under $3 including shipping.
i got the same readings from the F1 as you did, 12volt on one side nothing on the other (with the power cord plugged in), so i put a wire across it (F1) and the monitor worked. Fuse was obviously blown. i didn't know where to get that fuse or how to replace it so i just soldered a wire across both ends of the fuse and the monitor now works great. don't know if i blew it with the heat from soldering the capacitors or if that was the original problem, but it now works, just don't have that fuse protection, but i was ready to throw it out so what do i have to lose?
you article was fantastic, by the way. every step. just like i had someone next to me showing me how to do it, thanks.
bob

[SteveW]

rnearl, thank you for the additional info. I think you're the first person who has ever mentioned the temperature rating. I also don't know how likely it is to make a difference. It would depend on whether the components really ever get that hot. 85C is more than 180F, and 105C is hotter than boiling water, so if you touch a component and get a serious burn, that's an indication you're in that neighborhood! Whenever possible, though, I do agree that trying to replace a part with the closest match you can find is a good thing.

Your experiment with F1 was more daring than I would usually be willing to do, but I appreciate the report because it confirms that F1 is a fuse.

I would be rather worried running the monitor that way, however. The fuse protects the other parts, which doesn't matter because you were going to throw the monitor away, anyway, but it also prevents other parts from overheating and starting a fire, which matters a lot. So watch it closely, and maybe don't leave it running unattended. But it's really nice to know that that might actually be the remaining problem with mine and that in a real emergency (what constitutes a "real monitor emergency", I don't know) I could probably short the fuse and it would work, as long as that doesn't create some new emergency of its own.

[rnearl]

steve
thanks steve for the heads up on the fire danger. i never leave my computer running unless i am using it. now that i know that i can solder a wire to either end of F1 then i know i can solder in a fuse. my only problem now is to determine what size. obviously 12volt and very small?
by the way i also had an fdp1810 which is almost the same. one difference is that you need a 12volt power supply instead of the 110 to power the whole unit. it is exactly the same on the outside as the fdp1830. a  little different on the inside. the problem with this one again was the F1 fuse also. as soon as i jumped it, the unit worked.
maybe someone can come up with the right size fuse that can be soldered into this spot. i will keep an eye on the forum!
thanks bob

[SteveW]

The best place to find specs for the fuse would be a schematic of the inverter board, but I haven't been able to find one for the Ambit 6633tza015amss board. The second best would be to find a website or business specializing in monitor repairs and ask them if they're familiar with this board and if they happen to know the fuse specs. 

This type of fuse appears to be called a "surface mount fuse". Others that I looked up but appear to be wrong were "micro fuse" and "pico fuse". An image search on surface mount fuse helped to confirm that this is the right ballpark.

I found the Wikipedia article on fuses somewhat useful, and it shows how to decode the markings on a few types, but I think not for the surface mounts.

I have an old copy of "Littelfuse Product Guide.pdf", probably still available at http://www.littelfuse.com, which has a bunch of surface mount fuses. I'd bet the correct one is there, if only the markings on the blown fuse could be decoded.

At the moment my monitor is fully assembled and packed up in its box, so I can't easily get to the inverter to check out the fuse markings. I don't actually remember if it has any markings or not. One website says surface mounts often have no markings, making identification "very difficult or impossible".

[doubledge]

WOW - OK, Where to start....
After reading about what a hard time you had removing the 4 caps, I started really wondering just what was going on here. Then, I checked the link at Lockergnome and found more of the same.
Did soldering techniques somehow change overnight?  (overnight plus at least 2 years - when most of these boards were created)
I've been doing this kind of stuff for many years, and you almost scared me away with the horror story you've written here. Almost.
Had to give it a try - just to see what all the fuss was about. 
Keep in mind - I'm pushin' 60, been retired/disabled for several years (not actively working in the trade), blind in one eye, deaf in the other, hands go numb from circulation problems, etc., etc.

I figure any tech worth actually holding that meager title should be able to pull this off in less than 2 minutes. - I know I would have, back in the day.....

AND TO PROVE MY POINT, I CREATED A LITTLE VIDEO "HOW-TO" FOR YOU TO WATCH - it's uploaded to YouTube, and you can watch it by clicking this link:

http://www.youtube.com/watch?v=GmxD9YMID0M

PEACE ! 
=doublèdgè=

[SteveW]

Double WOW, doubledge, well done!   First a couple of confessions... 1) that's the first YouTube video I've ever viewed. Is this YouTube thing something new?  2) I'm on dialup internet, and that is well worth the download time, whatever it was, 15-20 minutes or so.

You make it look easy. That's how it should go.

One thing that has changed in the past few years is the use of environmentally friendly low (or no?) lead content solder on PC boards. The new solder has a significantly higher melting point than the old lead/tin, and in this I think your cheap-o soldering iron was probably a big help. My (supposedly) 60-watt temperature-controlled old Weller soldering iron (whose temperature control was for lead/tin) kept cycling on and off trying to maintain a constant temperature, when in fact it should have stayed on continuously because it never developed enough stored heat to melt that solder in a second or two like yours did. So for this job a simple clunky soldering iron without temperature control is much more suitable. The faster you can get that solder hot, really hot, the better it will go.

[neilam]

My son gave me a dell FPD1830 monitor that wasn't working. The fuse is missing on the power supply board P/N 6870T536D11. Could anybody tell me what the aperage of that fuse is. I tried a 2 amp but it blew. On the board the number above the fuse is F901. thank you

[dcandmc]

Steve-
Great write up.  I have a nearly six year old FPD1830 that was flickering at start up, to the point that it took 200+ cycles of the SOURCE/SET switch to finally get the image to stay on the screen.  I found your tutorial via google, bought the capacitors from RS this morning ($5.42 with tax), and completed the repair.  I now have a monitor that performs as designed.  The YouTube video by doubledge was also very helpful, as I used his method to remove the bad capacitors.  I then used desolder braid to remove all the old solder that I could, and I reamed out the holes with a micro awl.  I am at best a beginner solderer with a cheapo RS 30W iron, but I was able to get it done OK.  My only "oh crap" moment was when I realized that I had removed the old capacitors without noting the orientation of the negative lead.  I want back to doubledge's video and could determine with reasonable certainty that the gold stripe on the caps indicating the negative lead was on the side closest to the edge of the board.  Anyway, thanks for sharing your knowledge and taking the time to publish all the details.

dc

[moe]

To All,

I found the articles most interesting as my 2002 FPD1830 went black while viewing. My father who is in his late 80's and wears two hearing aids and has two metal hip joints was getting out of his chair and touched the corner of the computer desk for support and the screen went dark. I put a volt meter electode in each of his hands to see if he was emmiting an electric charge. It read the same for him as me. So it was just a coincidence that the screen went dark the instant he touched the computer desk which is wood unless he had a large static electric charge.

Anyways I took the 1830 monitor apart on my own as I am a tinkerer. I found a T3.15AH 250V fuse in the power supply circuit board. It checked out ok with my voltmeter. After doing much research on this type fuse I have concluded that it is a delayed fuse of ceramic type, 5X20mm size, slow blow. I think the H means it is delayed and the T means it is slow blow not sure what the difference is between delay and slow blow. I could not find a fuse like that searching the internet. But the one I have in the 1830 checks out ok.

Once I got the steel cage open and saw the components I hit a brick wall because I didn't know what any of the boards were or what they did. I saw high voltage warnings and figured latent voltage could be in the large capacitors.

I put it back together and went back on the internet to see if I could find anything on this video monitor. Came across this website and read the article posted by Steve. It was a truely amazing article because I have had so many experiences like that as a tinkerer. And then I watched the uTube video showing the capacitor replacement and me thinks that guy is GOD.

Another enlightening piece of information I garned from Steve was that I could take a bright light and put it up to the video screen and see the material being displayed. I had no idea that could be done. I can actually see the words even though the screen is dark. The power on light works but the screen is dark.

Now to fix my video monitor me thinks I need the capacitors replaced on the inverter board. Or maybe that F1 fuse is blown on the inverter board. Can anybody help me here?

Thanks,

Moe