Lcd Monitor Flickers & Goes Black

ttwiv · Joined: Mar 10, 2007 Posts: 5

I have no clue how you guys got the new capacitors soldered on to the old board. I worked for a long time trying to get the capacitors off (with a soldering iron and sucker) -- to no avail, so I just pulled them off leaving the old leads sticking up -- then tried to solder the new capacitor leads to the old leads -- but that was impossible. It's too tiny...

...does anybody know of a place in the Denver area I can pay to do this for me?

j777dragon777j · Joined: Feb 05, 2007 Posts: 6

Luckily I had a friend who is an electrician and good with fixing stuff like this and computers do it for me. He said it was pretty intricate but he did it and mailed it back. I just replaced it tonight and I'm using the monitor now. So far so good!

goretsky

Hello,

I would think that any place which fixes electronics (stereos, TVs and so forth) would be able to replace the capacitors for you for a nominal labor fee.

Regards,

Aryeh Goretsky

SteveW · Joined: Apr 03, 2007 Posts: 7

Hello,

I found this thread the same way it seems everyone else did, while having the exact same problem with my FPD1830.

I was able to replace the capacitors, and it solved the problem, but it was an ordeal.

I wrote an article containing step by step instructions for doing the replacement and describing ways you might avoid the mistakes I made. It is at http://25yearsofprogramming.com/blog/20070403.htm . Any comments, criticism, and especially corrections are welcome and appreciated.

Someone asked what the part numbers were for doing the replacement. The Radio Shack part numbers are #272-1028 (35 Volt) and #272-1044 (50 Volt). Those two are the same physical size; either can be used.

ttwiv · Joined: Mar 10, 2007 Posts: 5

Wow -- that's quite a detailed article. I wish I would have read it before I started my project. Nice job. I've got my Gateway monitor taken apart and capacitors pulled out with about .5" of lead wire remaining in each hole (eight of them still soldered in). I noticed in the post you said the capacitors are soldered in in-series. Rather than deal with removing the old leads, can I simply solder my 4 capacitors to each other, then solder each end of the chain to the 2 old leads on the far sides of the row of 8 leads?

I also forgot to note the polarity before removing the old capacitors. But I believe the negative end faces toward the outside of the board (based on the circle markings where each capacitor goes) -- is that correct?

SteveW · Joined: Apr 03, 2007 Posts: 7

LOL, I wish I'd written it before I started my project! But I only finished and posted it a couple of hours ago.

Wow, if you've got .5" of wire remaining in each hole and none of the solder pads disconnected or damaged, it sounds like you're in good shape. My old capacitors didn't have .5" of total lead length to start with.

The capacitors are in parallel, not series. (So their total capacitance is 400 microfarads.) If you look at the foil beneath the green lacquer of the board, you'll see that all the negative leads attach to the same big slab of ground foil, and all the positive leads attach to a different slab (it's harder to see how those ones are connected; I think it's on the top, component, side of the board).

So in other words, it's as though all the capacitors are soldered together with all the negative leads soldered together and all the positive leads soldered together. NOT negative-positive-negative-positive... etc. soldered into a chain.

SteveW · Joined: Apr 03, 2007 Posts: 7

Ok, I just reread your earlier post and saw that it was impossible to solder the new leads to the old ones.

How are you with desoldering? And is there enough of the old leads sticking up to grab securely with needlenose pliers?

If you don't have desoldering experience, find an old board and get some good practice for a while.

If you can hold the old leads with pliers, there really is a good chance you can get them out. The worst of my problem was that there was absolutely nothing to get a hold of.

[edit]
If you don't feel confident about this, goretsky's idea is a good one. A stereo or tv repair shop might be willing to do this for you. Since you've already got the board out, they'd be spared most of the time-consuming and costly hassle of the job.

ttwiv · Joined: Mar 10, 2007 Posts: 5

Thanks Steve for the reply. I did try taking it to a TV repair shop, and the owner of that particular shop said they make the boards now-a-days so you can't replace parts -- so he always buys new boards; which as you pointed out isn't a bad idea.

Yes, I said it was impossible to solder the new capacitors to the old leads, but that was in context with my soldering experience and tools. I have a friend that I asked about this, and his reply was:

Werebo

I don't know what they're called in the USA, but here in the UK, we have what's called 'Solder Suckers', a spring-loaded reverse pump type gadget. press the plunger down, hold the nozzle to the molten solder on the board, press the button and all the solder/loose snippets of wire gets sucked up.

1 point to bear in mind though, lots of modern circuit boards are 'multi-layered', having several boards and tracks bonded together. Too much or prolonged heat can very easily damage these boards, not to mention the components.

If deciding to repair these types of boards, DO use a heatsink on the component legs and keep the heat exposure to a minimum.

slowjoe · Joined: Apr 08, 2007 Posts: 1

Hey guys....I just obtained this model monitor from my uncle who was about to throw it out for the same flickering reason....when i removed the 4 capacitors i simply pulled straight up on them with some pliers and the metal plates that were connected to the board stayed put! In other words they were sticking straight out of the board and I simply soldered each capacitors lead to these metal posts from the old capacitors. hope this helps!

SteveW · Joined: Apr 03, 2007 Posts: 7

That's a great tip. Thanks for posting it. I still have the little green capacitors that I removed from the board. I tried pulling the legs out -- they came right out!

One way to solder two pieces that are small like this is to melt some solder onto each part separately. Then place the two parts next to each other and apply the soldering iron to them. The solder will melt almost instantly and fuse them together. The drawback is that the connection isn't mechanically secure, so it's less than ideal.

DavidIQ · Joined: May 18, 2007 Posts: 1 Location: Earth

Thanks for the tip on the capacitors Very Happy

My wife's monitor at work (the Gateway 18" LCD) went out and they replaced it. Rather than throw it away she convinced her boss to let her take it and recycle it. When I got it I searched and found this topic and it was just what I needed.

Got the 50v ones from Radio Shack...that's the only one they had 4 of. I have to say though that I got one heck of a scare when I plugged it in and turned on the monitor. I heard a fizzle and the screen was flickering then POP! I opened it back up and found that one of the new caps had blown (it was bulging) but before I did this the monitor seemed to have been working fine without it. So I decided to leave it how it is and use the monitor. Working like a champ! Wink

Good thing the blown one was the one at the end of the circuit and not the beginning. Rolling Eyes

Thanks for the great idea guys!

Total cost: $5 and a couple of accidental burns from the soldering iron...still learning!

dwelk · Joined: May 20, 2007 Posts: 1

mouser has about 143k capacitors - can you recall specifically which you ordered - thanks!

Panthera75 · Joined: Jan 19, 2007 Posts: 5

Ok, so I finally got around to getting mine fixed. I gave a Gateway FPD1950 and have been experiencing the same type of problem for several months. I called around but there was nobody I could find that could fix it except for ONE business. I took it to them, they got back to me the next day but it cost me $80 and they had to change out 7 capacitors. Anyway.. so that was Wednesday, then today when I woke up the screen seems to be darker on the bottom than on the top. Could this be the result of the capacitors being changed?

goretsky

Hello,

It could be an issue with the capacitors used or with the monitor not being reassembled properly. I would suggest you contact the business which repaired the monitor for you and ask them to check it. Since only a couple of days have elapsed since the repair it should still be under warranty.

Regards,

Aryeh Goretsky

Panthera75 · Joined: Jan 19, 2007 Posts: 5

Yea I suppose you're right.. I just wasn't sure if they could fix that too.. and I really didnt want to spend any more money. Oh but if its under warranty, I shouldn't have to pay right? Smile

Ill call tomorrow.. thanks!

lafaverp · Joined: Jun 02, 2007 Posts: 1

I don't know how much this will help but, I confirmed from Gateway that the monitor blackout issue ( I have a FPD2185W) is a known problem to Gateway. Their solution: replace the monitors in warranty and for those of you, like myself who are are out of warranty (5 months) um, let's see how did they put it?... oh ya "Screw you. Thank you for calling Gateway.") I replaced my 21 inch that cost me $600 17 mo. ago for a Viewsonic 22" for $299 at Costco. Wow! what a picture! Got a slice of pizza and one of those 5 gallon jars of 3 bean salad too. Laughing

Panthera75 · Joined: Jan 19, 2007 Posts: 5

Welp, my monitor died that very night of my last post. The people who "fixed" my monitor, aided in killing it. lol Anyway, I suppose I was due for a new one.. so I bought a Samsung 22" Widescreen, and I'm very happy with it! Smile

AlzoDYS · Joined: Jul 29, 2007 Posts: 1

This topic was so helpful, that I registered just to give my thanks. The solder job was difficult (being my first time and all) the solder points are pretty weak, should I have to worry that it might cause problems( like a short circuit, or it coming apart) thanks in advanced. Very Happy

SteveW · Joined: Apr 03, 2007 Posts: 7

Without being able to look at it, it's impossible to say how good or bad a soldering job it might be.

What I'd suggest is to do a web search on soldering to find sites with descriptions of proper technique and pictures of what good and bad solder joints look like. Then take some old scrap parts and do a lot of practicing to get the hang of it. Compare your results to the pictures as you go. With some more practice, you'll be better able to judge how you did on the monitor.

The important things with soldering are:

1) The parts that are supposed to be connected ARE connected, and will stay that way.

2) There are no blobs or drips of solder that accidentally connect parts that are NOT supposed to be connected.

If your monitor is working and hasn't made bad sounds (crackling, hissing, sparks, or pops) or have a burning smell, then you are probably ok with regard to 2) and don't have any short circuits.

Things would probably only come apart if the solder was applied when the joint was so cold that the solder is barely sticking the parts together, or if you used so little solder that it can't handle the current going through it and might melt or crack over time. Even if that's the case and it did come apart, the chances are fairly good that it would only cause your monitor to stop working again. The wires wouldn't be likely to "fly apart" and short circuit unless they were under tension and sprung apart with a "boing". But if they were under tension, you would have had a hard time soldering them together in the first place. So they would be more likely to just gently let go and the monitor would stop working.

If wires are so close together that you're worried about short circuiting, you could stick little pieces of electrical tape between them.

Also, you could show the board to someone with more experience and see if they think it looks ok.

If it's working, though, remember that if you go back in and fiddle around, there's always the chance of making it worse instead of better.