Replacing LCD CapXon Caps

[Agent24]

Re: Replacing LCD CapXon Caps

That's just glue. It's used during assembly so things don't fall off. You don't actually need it.

Incidentally, some kinds of glue can turn conductive over time and cause problems. So that's another good reason to stay away from it! (and also why some things fail)

[biatche]

Re: Replacing LCD CapXon Caps

What do you call these white ?insulation? paste http://www.anandtech.com/show/2433/6

I should get some.

[Agent24]

Re: Replacing LCD CapXon Caps

I got the thinking that, in order to "limit" a product's life.. they could be stressing out components, well like capacitors! If so, what could actually cause the caps to bulge? Overvoltage? Undervoltage? Capacitance too high? too low? Ripple below recommended? ESR slightly higher than recommended?

Which would it be so that I'll go out and purchase capacitors higher rated than the ones i pulled out.

It's usually simply because the original capacitors are crap quality.

[biatche]

Re: Replacing LCD CapXon Caps

I'm going to purchase a new solder wick. (2mm seems a bit small and difficult..)

My eyes are on

3.9mm wide oxygen free copper
5.3mm wide rosin oxygen free copper

which would you choose? I feel 5.3mm is rather too wide... but I'm not sure if being extra wide causes for-now-unforeseen problems.

Maybe i'll buy some liquid flux.. not very sure if that flux pen works at all haha... or im using it wrong. Any tips on liquid flux? Also, how do i clean off flux, alcohol?

Would like to ask also... why do caps go bad? I've noticed high end power supplies use "branded" caps, true. Bad power supplies use no-name caps. But this cannot be the only possible conclusion.
I got the thinking that, in order to "limit" a product's life.. they could be stressing out components, well like capacitors! If so, what could actually cause the caps to bulge? Overvoltage? Undervoltage? Capacitance too high? too low? Ripple below recommended? ESR slightly higher than recommended?

Which would it be so that I'll go out and purchase capacitors higher rated than the ones i pulled out.

[mariushm]

Re: Replacing LCD CapXon Caps

60/40 stays liquid for more time. So 60/40 would help you a bit when desoldering, as you can heat, put down the gun and maybe still have time to pull out a capacitor with the hand you kept the tool in while the solder is still liquid.

But at the same time, you could just add solder to the leads, grab your solder wick and heat it up with the solder tip until the solder on the leads simply "crawls" up the wick, leaving the holes nearly empty.

So no, 63/37 is overall much better imho, being eutectic and the advantages outweigh the cons.

Maybe you weren't patient enough to heat the wick until it was "ready" to do its magic. Sometimes it also helps to put a drop of liquid flux on the solder wick and the soldered leads and it also helps to move the wick slightly near by the solder so that it gets on new surface.

Here's a pretty good video showing how solder wick works: http://www.youtube.com/watch?v=htrcZuK_ZsY

I'll be honest and tell you my solder wick doesn't work as nice as his, but when I apply a bit of liquid flux on it and the soldered leads it's nearly as nice as in the video.

[biatche]

Re: Replacing LCD CapXon Caps

If you're interested to know, I've successfully revived the monitor with all the recommended items you provided, not to mention with bad solder work. I guess experience is needed. That braid was rather thin though. Didn't quite like that. Had difficulty getting the solder to stick to the braid.

OK, many thanks for your replies.

BTW: for desoldering, is a 60/40 better? I notice adding some solder helps in desoldering.. then i couldnt help but wonder if a 60/40 would work better for that.

[mariushm]

Re: Replacing LCD CapXon Caps

I did have flux hit my face in the past (had to put some liquid flux on an oxidized connection and boiled when i put the solder tip on the pad)

So I got one of these: http://my.element14.com/north-safety...ame/dp/1762958
They're clear enough they don't bother me at all when working, they're much clearer than what the picture shows.
These will probably work just as well: http://my.element14.com/north-safety...gle/dp/1696197

They're rated only for protection against dust but they will probably also protect your eyes from broken drill bits and other things, they just don't have that rating.

I just use some tweezers that came with nail clippers and other things my sister uses. Technically it's not recommended because they can get charged with electrostatic stuff or get magnetic but I don't work with so sensitive equipment to care.
I guess if you want, you can get the ones in the first link.

[biatche]

Re: Replacing LCD CapXon Caps

It just occurred to me.. will I need decent tweezers to hold caps? Searching element14.. there's a whole range of these goods...

http://my.element14.com/proskit-indu...pcs/dp/1666210
http://my.element14.com/arexx/at-700...tic/dp/1280092

Are goggles highly recommended for safety or are havocs very very very unlikely?

[biatche]

Re: Replacing LCD CapXon Caps

Okay.. you're right I haven't watched this. As funny as it may seem, I'll be getting my gf to watch it as she will be doing the soldering. My hand shakes as hell so I'm probably no good at this. I saved the links though, I thought I should watch them after purchasing. Incorrect assumption.

Now I realize, everything you say is very absolute.

Proceeding with purchase now.. a very big thanks for all the help and recommendations.

[mariushm]

Re: Replacing LCD CapXon Caps

Just don't buy a vise.

Your first choice is good.Go for the ~0.7mm ones if smaller diameter ones are no longer available in the Singapore location (I assume that's what's cheaper for you)

Yeah, no need to worry about lead, just wash your hands after soldering a lot. Lead doesn't burn when soldering, unless you eat it you won't have anything to worry about.

In fact, the flux inside the solder is what's making that smoke which is actually a bit bad for you - in time, it can irritate your lungs and throat. Generally, a simple computer fan blowing some air across the desk where you work and a ventilated room is enough, but there are fans with special filters designed to absorb that smoke.

I posted some links to a youtube tutorial about soldering just a few posts above - I see you didn't watch it as it explained all this. It's really useful and informative and shows you a lot of what I said, you should watch it.

[biatche]

Re: Replacing LCD CapXon Caps

Vice (revised):
acceptable? or can i just use my bear hands. if i eventually purchase the panavise i'd be spending more in total. do suggest. http://my.element14.com/dremel/26152...pcs/dp/1869045

Solder (revised):
Didn't notice it was 0.7x mm.. I swear I set 0.56 as the upper limit lol.

*my choice* cheap: http://my.element14.com/edsyn/ss5250...-5mm/dp/871436
double the price: http://my.element14.com/multicore-so...250g/dp/419564
worst candidate?: http://my.element14.com/multicore-so...50g/dp/5090787

Actually..
I did some googling on lead vs lead free. It does appear health concerning.. so I may secretly do away with a lead free version. It may be more difficult, especially in the beginning, but I think I should be able to get the hang of it in time.
My only concern is the higher melting point which may damage the pcb. Tough decisions. So maybe after all I'll just inhale some lead..

Update: Further googling suggests no cause for concern. Countries are worried about lead poisoning is more due to dumping lead products into the waters than lead inhalation. So I'll just buy the lead version and do the world more evil.

[mariushm]

Re: Replacing LCD CapXon Caps

I'd go for the Panavise one, but if you have limited budget save them for later, you will manage to work on boards without one of these, until you have money to get a proper one.

Solder, must get one with lead as I explained, it's much, much easier to work with.
Lead's chemical element is Pb, so you must get one that has Pb in the composition - the only one you list is the first which has 62 / 36 / 2 Sn / Pb / Ag or 36% lead.
The first is good, but a bit thick in diameter. Try to make an effort and get one that's close to 0.5mm or even thinner.

For reference here's my 0.56mm one - as you can see it's a bit thicker than the lead of a capacitor:

[biatche]

Re: Replacing LCD CapXon Caps

Solder station:
So it's decided that I'll be taking the Hakko FX-888. Done. $150 Real bummer. Getting overcharged here.

Vice:
It has to be one of these 3... it's actually over my budget already. I was thinking to do away with cheap beginner goods. I just needed something to hold. I hope I'm doing the right thing, it's quite the investment. Care to share your opinion?
http://my.element14.com/draper-tools...5mm/dp/1706192
http://my.element14.com/panavise/301...ose/dp/1653517
http://my.element14.com/stanley/83-0...ice/dp/1696668

Solder:
http://my.element14.com/multicore-so...250g/dp/419540
http://my.element14.com/multicore-so...50g/dp/5090866
http://my.element14.com/multicore-so...50g/dp/5091020
There's lead, and lead free... not sure about the flux part, but they have different 'flux types'

Is 0.5mm big?

[mariushm]

Re: Replacing LCD CapXon Caps

If you're sure you're going to work on other electronic devices, get a soldering station - if possible that Hakko model. It pays off in time, it's much easier to work with.

I wouldn't get the clamp tool with magnifier... it's a very cheap model that's not so good - I mean it won't be able to hold boards commonly found in monitors, video cards, it bends down from the weight. The base is not that solid also.

Something like this:

http://www.amazon.com/Ramsey-RTS13-P...4518822&sr=8-7

would be more suitable.
These Panavise things are recommended by engineers often: http://www.amazon.com/s/ref=bl_sr_in...xtbin=Panavise (you pick a base and then whatever you want on top, circuit board holder or whatever else)

No clean flux you should be able to find in local stores in larger quantities and a bit cheaper, though I wouldn't know how good it is. I personally bought from a local store a 50 ml no-clean flux bottle for about 4$ - that pen style flux is probably only 10-15ml.
Anyway, it will last you a long time.

You should also get some solder wire... get quality one with no-clean flux inside. Even with no-clean flux inside you will see sometimes you have to apply additional flux on the area you wish to solder.
You also need to add solder sometimes to the lead free solder on the pcb so that the heat from the soldering tool tip is transmitted onto the hole that's soldered.

Probably all you're gonna work with is lead free solder, but there's no point in buying that - you'll only have a hard time with it due to lead free's solder temperature, which is higher at about 217c.
Get one of the variants with lead... I personally use 63/37 but the most popular one is 60/40.

63/37 is euctetic meaning it turns liquid at a much narrower temperature range and it also turns solid much faster. This is good when you work with soldering wires on jacks or when you want to just remove the tip from the solder and see the solder harden in 1-2 seconds as the temperature drops.

60/40 has a much wider range, which means it's easier to work with when you have crappy tools, it stays liquid for a much longer time, and turns liquid faster... but the disadvantage is once you apply solder where you want to make a connection, you need to keep that wire and everything steady for a few seconds until the solder turns solid, otherwise you may get a poor quality soldering.

A 100g or bigger roll should last you a very long time - I personally went and got a 500g roll and it will probably last me 5-10 years.

The thinner the diameter the better, but pick something that has at least 2% flux, and that one preferably no-clean one.

Here's something that I would recommend :

http://my.element14.com/edsyn/ss5250...-5mm/dp/871436

60/40 http://my.element14.com/multicore-so...50g/dp/5090787

63/37 http://my.element14.com/duratool/spc...5lb/dp/1530151

(I'm reluctant to recommend the Duratool, it's somewhat of a "store brand", they're just rebranding stuff other people make. But this one is cheap and 63/37 being not so popular you only find it in 500g spools which is more expensive.

If you can, stick to Multicore, Kester Solder, Stannol, Edsyn.. these are established brands and you can be sure the quality is consistent.

There's also other varieties that have silver or copper in them - silver ones are better for soldering surface mount components as some SMD chips have silver at the ends so the chemical "gluing" is better with this kind of solder.

http://my.element14.com/multicore-so...250g/dp/419540

I don't think it's worth paying that much extra for this variety, even if you do work a lot with SMD components.

ps. and you absolutely need to watch at least part 1 and 2 from this tutorial:

http://www.youtube.com/watch?v=J5Sb2...ure=plpp_video
http://www.youtube.com/watch?v=fYz5n...ure=plpp_video
http://www.youtube.com/watch?v=b9FC9...ure=plpp_video

[biatche]

Re: Replacing LCD CapXon Caps

Thanks once again for the marvelous suggestions.. I haven't come to a conclusion with a solderer but I may be able to pick up the Hakko FX-888 for ~$80-100.. I'll need to make some calls Monday. In any case, I've the below in my shopping list.

1
1925200 1 CHEMICALS,SOLDER
KESTER SOLDER
83-1000-0951.
2
876835 1 DESOLDERING BRAID, 2.0MM
EDSYN
SW091/2.0
3
1367049 1 CLAMP TOOL, WITH MAGNIFIER
DURATOOL
D00269

I will be working on LCD monitors, psu, motherboard, gfx cards. POSSIBLY interested in making my own audio DAC in future...

So I guess that's about everything to get me started yeah and a little beyond?

[mariushm]

Re: Replacing LCD CapXon Caps

If you're just planning to repair this monitor, it doesn't really make sense to buy a Hakko FX-888 soldering station - it's kind of expensive.

The board is simple enough that you would be able to de-solder the old capacitors and put the new ones with cheap soldering guns. You should be able to just apply some flux over the old solder, add some solder over the one there, heat up both wires of a capacitor and pull it out from the pcb... then just push the new capacitor in, keeping the polarity the same.


For example, this 40w soldering iron one would work ok, if you're patient enough until it gets hot (about 3-5 minutes) :

http://my.element14.com/duratool/d00...lug/dp/1568161

For something better but not quite as good as a Hakko, this is OK:

http://my.element14.com/duratool/149...-eu/dp/1737236

If it costs 80$, it's a good deal.

If you're willing to buy a quality soldering station, the Hakko FX-888 is a very good one. Generally, the 240v ones are marketed towards the Europe and Australia and they're very expensive compared to the 120v station.

However, there's a version available made for the Chinese market, which is cheap and should have the same standards of quality:

http://www.dealextreme.com/p/hanko-f...ac-220v-126505

I don't think you'll need a solder sucker... I don't use them. Solder braid would help: http://my.element14.com/edsyn/sw091-...-0mm/dp/876835

Flux definitely helps - try to get a "no clean" one, for example this would be ok:

http://my.element14.com/kester-solde...der/dp/1925200

With others that are not "no-clean" you would have to clean the pcb area with water or with isopropyl alcohol after soldering.
You might find cheaper flux locally, but the one I linked is very good.
The holder is also not really needed and if you get a soldering station, they come with one.

[biatche]

Re: Replacing LCD CapXon Caps

1
1831277 4 CAPACITOR, RADIAL, 25V, 1000UF
RUBYCON
25ZLJ1000M10X20 RoHS Compliant Yes
2
1144699 4 CAPACITOR, 220UF, 25V
RUBYCON
25ZL220MEFC8X11.5 RoHS Compliant Yes
3
1281814 4 CAPACITOR, 220UF, 25V
RUBYCON
25ZLG220MEFC8X11.5 RoHS Compliant Yes

These items are in my shopping cart now.. and yeah I bought a couple of extra's since they are cheap... not sure if that's too many extras or unwise anyhow.

My eyes are now on the Hakko FX-888 soldering kit?station? What else do I need?

solder sucker? pump? braid? flux? I should get a holder.. hmm...

[jsog]

Re: Replacing LCD CapXon Caps

Panasonic FR 10x20mm: http://my.element14.com/panasonic/ee...0uf/dp/1907238.

[mariushm]

Re: Replacing LCD CapXon Caps

Rubycon ZLJ is OK.

The Panasonic one isn't - its ripple value is only 680mA - the old capacitor has 1650mA ripple and 0.045 ohm imp/esr , so you should get one that has at least about 1300mA ripple.
Same story with VZ.
You really have to look inside the charts in the datasheets.

Anyway, not much out there other than the Rubycon ZLJ, at those diameter and height restrictions.
If you go to 20-23 mm height and maybe 12.5mm diameter you have more options.

As for the 220uF, I stopped at those 3, Panasonic HE or FM and Rubycon ZLJ. But there's tons more models that fit your needs, especially if you have 18-20 mm of height you can play with. From those three I gave you as example based on your restrictions (diameter and up to 12-16mm height), The FM and ZLJ are the better ones according to specifications. But you can pick whichever comes out cheaper at the end, all three are good.

[biatche]

Re: Replacing LCD CapXon Caps

Great forum, no, you're great. So much details to help this beginner me.
http://my.element14.com/jsp/search/b...alues%3D202457

Options:
RUBYCON - 25ZLJ1000M10X20 - CAPACITOR, RADIAL, 25V, 1000UF
http://my.element14.com/rubycon/25zl...0uf/dp/1831277

PANASONIC - ECA1EHG102 - CAPACITOR, RADIAL, 25V, 1000UF
http://my.element14.com/panasonic/ec...0uf/dp/1848543

NICHICON - UVZ1E102MPD1TD - CAPACITOR ALUM ELEC, 1000UF, 25V, RADIAL
http://my.element14.com/nichicon/uvz...25v/dp/1822672


I hope I did well. A "B-" will do.

So..
220uF: Nichicon HE vs Panasonic FM
1000uF: Rubycon ZLJ vs Panasonic EH vs Nichicon VZ

How do I judge which one's best? How should I make my decision from here?