Frustration trying to repair a LCD

[Drew@PSU]

Ok, so I have a Viewsonic VX922 that went bad last year, so I said, well, let's see why. After about 2 hours of disassembling the monitor ( a major pain ), I found some bulging caps. I picked up a soldering iron at Radio Shack, some solder, side snips and a desoldering braid ( I also ordered the caps ). I read up as much as I could, tinned the tip of the iron, and got to work. I tried to use the soldering iron to heat up the solder on the bad caps and stick the braid in there as well. It's a 20/40 watt, and I cannot for the life of me get the solder to melt at all. Whether on the cap solder points, trying to solder some wires together, ever. I wonder if the thing is even getting hot, but sometimes it does actually melt something. It's seemingly random, so I figure, ok, whatever, get what you pay for. So I ordered a 260/200 watt Weller soldering gun from Amazon. Plugging it in and trying again today, I try the RS one. Still no dice. So I plug in the Weller, only to find that instead of melting the solder ( anywhere ), it's just burning/melting/reacting with the tip. In fact it's making a horrible stink, so much so that I said screw it and made popcorn to cover up the smell. I'm very frustrated, because I can't see what I'm doing wrong. At this point, even if I torch the LCD totally, I'm not too worried, I just want to be able to get farther than taking the whole shebang apart and getting stuck. I'd love to take a MAPP gas torch to it, but I don't think that will help. </rant>

tl;dr: Frustrated trying to solder, need help.

Anyone have any ideas/explanations?
Thanks in advance,
Drew

 

[torin3]

There are some decent soldering/desoldering tutorials on Youtube that may help you.

Some other things you might consider. Adding some fresh 60/40 solder to the solder already on the caps. It will help lower the melting point of the solder.

You might pick up some flux. Brush on, pen, liquid, it doesn't really matter which form, but it should help you.

Edit:

Also, tinning videos:

Hope that helps!

 

[Psycogeec]

been there done that
you should have been able to pull it off with the 40W core.
but more and more these PCBs (the curcuit board thing) is loaded with copper , layered , and has things called VIAs, copper holes which shift the heat around.
SOME stuff (not nessiarilly what your working with there) the board is a big bloody heat sync, that sucks all the heat out of the solder gun before the "new Improved" non-lead solder and high temp solder even melts.

Torins tip of melting new fresh solder on can get a thermal conduction going by having liquid solder wrapped (more) around the tip, as opposed to a few molecules of heat conduction trying to break through the solder blob. and can add back flux from a cleaned (of flux) blob. but if the tip goes cool, nothing will budge.

i got tired of being beaten by all this heat syncing, and weasily little solder guns, and re-thought out the whole thing.

Why is the gun freezing on contact
Really "pro" pencil soldering guns, like on $100+ temp controlled stations, have big copper cores. even if the heating element isnt huge, they dont go cold on contact so fast, because the CORE is still blazing hot, and keeping the tip hot.

dont FIGHT it , it will win no mater how long you try and war with a solder blob if it didnt melt when you hit it with the HOT tip, it wont by holding it there any longer, cause the tip isnt Hot anymore. you must stop wait till the tip and/or core is back up to screaming hot, then try again.

soo 140 200 even 250+ or whatever it was wellers, the heater is there, but there is no "core" to hold the heat. so again the same thing applies, if it didnt work at first, it wont, you have to back off get the tip hot again, and take a run at it. I fried 2 wellers over time, trying to do fat stuff , and heat synced stuff, the tips contacts come undone easily, and by the time you Fight things over and over again, they burn themselves out, because they are designed for intermittant use.

i went and bought the crafstman 150-400W Pencil gun, yup i wanted major wattage, but with a big core to hold heat. and i can melt huge solder blobs on all sorts of things now.
&#&@$^ i beat the thing. Its a pencil , its a gun, but the main thing is it has a huge core that holds the heat.
so if you cant afford a good primo copper core temperature adjust soldering station, check out sears for the craftsman pencil gun at 1/2 to 1/3rd the price.

sure it isnt designed for working with smaller components, but if they tick me off enough it will certannly remove them fast enough.

also some of the battery operated ones, will get hot FAST too, but they didnt last any time at all, torturing them.
some of the pencil butane ones get hot enough, but so much side shooting waste heat was problematic, burn me, burn some wire etc, and they didnt last time either
and neither of those had the Core, they just had lots of "power" like the weller.

and tips have to be clean, or they dont conduct heat with the junk insulating them.

solder WIck, will pull solder off allowing you to remove a component, but it is more usefull for cleanup, than for through Hole component removal

a Solder Sucker will suck the solder off the blob AND through the hole, holding the wire. so when removing wired through board components a solder sucker will clear the holes better. and BULB suckers dont suck enough. the spring loaded suckers that look like this
http://www.qwikfast.co.uk/catalogue/images/silvsoldsucker633609.jpg
put the smack down on the solder in one quick move. you just get the solder point hot enough, then QUICKly "seal" the solder sucker right on top of the solder blob, and click.
Wick is still easier, but if the component is (say) purposfully soldered deeper into the hole, only the solder sucker will clear the hole.
once you get a good hot clearing of the hole, the part might have a teeney bit still holding it that can be manually freed by pulling hard.
.

 

[Drew@PSU]

Thanks for the help guys,

torin3 - Yeah, I guess I'll try it again with the tinning. My problem is more the fact that the irons don't get hot enough, or consistently enough (probably related to the tinning).

Psycogeec - I'll have to clean off the tips, is sandpaper too much? Do I risk removing too much from them?

The Weller made such a stink from melting whatever the hell was on the tip for shipping that it stunk up my whole apartment. I'll get a picture of it a little later, it's kinda weird. It looks like the finish on it started bubbling up as it got hot, rather than transmitting the heat to what I was trying to solder. Is this because I didn't tin it? Does anyone know why that happened? Do I need to sand it first or something?

Thanks again,
-Drew

 

[Psycogeec]

your not supposed to sand or grind a solder tip. just get a sponge or a folded up paper towl, and get it fully damp, then drag the hot point against it quickly.

now with that said, when a tip is finnaly fully rotted from flux and time on and all, i do grind, sand, and belt sand them. but they have a coating most the time, that keeps the flux from eating them. it is good to keep it alive, until it is gone anyways.

the stuff on the weller tip was probably flux, and it is pre-tinned, flux goes from solid to liquid to smoked off, depending on the temps.
flux is not supposed to be breathed, as it will condence again in your lungs , and solidify
i think most of the time the solder gun itself has to be hot enough to fully smoke flux, but i havent used temp control, so mabey they dont have that?

ok solid, liquid, Vapor, and smoked
.

 

[TorqueRanger]

I use a poopy cheap weller and that works the best for me and the ones that you buy from radio shack just suck rear-end and invest a good spool of solder it help out with flow of solder!!!! If you need future help i will post a vid of what ever you need help.. Just let me know and i will get it asap for you!!! I bought a 19" for 10 buck and all was wrong with it was a loose wire lol and it was almost brand new...

Removed swearing. Please refrain from doing that. Thanks! -hokie

 

[GIXXERGUY6]

I use a poopy cheap weller

Removed swearing. Please refrain from doing that. Thanks! -hokie

LOL hokie made him say poopy

Ok sorry I had my gradeschool moment for the day.

I use steel wool to roll the tip through in order to clean it up..

 

[Owenator]

I agree with the advice above. But I'm no soldering pro just a DIY repair type.

I bought a desoldering iron from RS that has a built in bulb and a tip with a hole to go
over the "post" of the com[ponent being removed. The tip looks like it may have enough mass to stay hot but maybe not.

Also once you do get the caps out make sure you install the new ones with the right polarity. I just fixed an LCD myself this way but my first attempt I got the polarity wrong. Once I corrected that the LCD is now working again.

I like your repair ethic. "Don't throw it out if it can be fixed" is my motto!

Best of luck!

 

[TorqueRanger]

Sorry for swearing!!!!!!!!!

 

[Drew@PSU]

First off, thanks for the extra help, I know this is a little late in coming, but my STi had transmission issues, so that was kind of the big thing for the past month.

Psycogeec - Yeah, probably not the first time I've inhaled something bad for my health, I'll see if I keel over anytime soon.

GIXXERGUY6 - I'll have to put steel wool on the list of things to try, thanks.

Owenator - I figure if I can actually fix the caps, it's basically a free monitor + some new skills. My brother was using it for the year I was deployed and the problem it was having intermittently (not coming out of standby mode) became constant. So even if I totally screw it up, it's not like it was perfect to begin with.

I gave it another go today, and here are my observations:

-The tinning just doesn't happen for the iron. I manage to get it nice and hot and the solder just runs right off it. I tried both the 60/40 solder+flux and the silver-bearing "high-tech" solder that's much skinnier to no avail. In fact, it cuts the small diameter stuff like a knife, which while cool, is ultimately useless.

-Melting solder onto the blobs on the board is very hard for me to do. I managed to get a little blob on there and when I put the iron back on, it just melted off and didn't help pick up the component solder. It was a small enough blob that it cooled off and became a very tiny irregular ball bearing.

I'd like to get it finished and on my desk instead of my work bench, not sure what else I need to try to get this done. Any further advice is appreciated, as I'm not sure there are many people around who do this for cheap.
Thanks again,
Drew

 

[Owenator]

First off, thanks for the extra help, I know this is a little late in coming, but my STi had transmission issues, so that was kind of the big thing for the past month.

Psycogeec - Yeah, probably not the first time I've inhaled something bad for my health, I'll see if I keel over anytime soon.

GIXXERGUY6 - I'll have to put steel wool on the list of things to try, thanks.

Owenator - I figure if I can actually fix the caps, it's basically a free monitor + some new skills. My brother was using it for the year I was deployed and the problem it was having intermittently (not coming out of standby mode) became constant. So even if I totally screw it up, it's not like it was perfect to begin with.

I gave it another go today, and here are my observations:

-The tinning just doesn't happen for the iron. I manage to get it nice and hot and the solder just runs right off it. I tried both the 60/40 solder+flux and the silver-bearing "high-tech" solder that's much skinnier to no avail. In fact, it cuts the small diameter stuff like a knife, which while cool, is ultimately useless.

-Melting solder onto the blobs on the board is very hard for me to do. I managed to get a little blob on there and when I put the iron back on, it just melted off and didn't help pick up the component solder. It was a small enough blob that it cooled off and became a very tiny irregular ball bearing.

I'd like to get it finished and on my desk instead of my work bench, not sure what else I need to try to get this done. Any further advice is appreciated, as I'm not sure there are many people around who do this for cheap.
Thanks again,
Drew

I have an STI too! (07 from when renamed to STI from the previous STi). If you haven't already check out www.nasioc.com - good site for us subie guys. I'm Owenator on there too.

Back on topic: do you use flux on the iron before you try to tin it? I think the acid in the flux helps to etch off the surface metal making the solder bond better.

 

[Enablingwolf]

I am far from a great soldering person. I do however seem to have a large chest for soldering tools though... I do have a few tricks that I use in conjunction with them tools..

Have a small fan for the work area. (I like the fan to pull away not blow at me.) You want to ventilate.

For cleaning/tinning tips, acting like John Wayne. (Rough, tough and don't take crap for nothing.) I grab a brown paper bag. Rougher the better. And just use it like I would a sponge. The advantage here is the abrasive nature of the brown paper. Just make sure it is not overly wet, and not too dry. I use this regularly for my cleaning tips. Since they get junk (lots of flux) on them and the bag. So I toss out the paper and do not mess up my very nice and purdy sponge.. Oh and I bag polish the tips prior to fresh tinning. Impregnating the paper with flux first sometimes helps with cheap crappy tips.

Couple of items that are handy for many projects. An Exacto knife set and also a set of cheater glasses.

Make sure the set is not only cheap, but you can get fresh blades for the handles. Exacto knives are addicting, sicne they are more than cutting tools. (more on this further down)
the cheater glasses are simple and cheap magnifying reading glasses. I like to use the shortest/thinnest/tiniest lenses I can find. Which is usually a dollar tree or the like. Now the reason I like theses. They make small work closer and in turn you do not need yer face in the work. Plus you can see the work in more detail. Added bonus: sort of acts like safety lenses.

Now for the part where I mentioned above about the exacto not just being a cutting tool. I use my exacto to pry also as I remove solder. sometimes I even will scrap some material off the surface to get at where I want. Or even make strategic cuts to open up a joint some. (Depends on the project and what I am doing)

Keep in mind. Not all tips are good and you may benefit getting some new ones. I got about 20 tips along with my largish Weller station. It helps having a few irons also I guess. I found out, not all tips work good or are worth the time using them. Tips are not very expensive, so do not worry much about ruining them. You want the tool to work! Worry more about the iron itself.

 

[Drew@PSU]

Hmm....I have many things to pick up it seems...

Owenator - I didn't use flux on the iron, I will have to grab some and try. <OT>Yeah, I'm SubyDrewski on NASIOC </OT>

Enablingwolf - I've got a small fan sitting just behind the work that blows out towards the open windows ( at least when I'm trying to work ). I've added a brown paper bag to the list of things to pick up ( gotta get groceries tomorrow anyway ) so I'll try that. I've got a third hand with a magnifying lens(sp?) on it as I'm a sucker for neat tools, but I find it just gets in the way. PRK was great for the vision so I don't have trouble seeing what I'm working on too much.

I'll probably get more time to work on it this coming weekend, we'll see. Thanks again.
-Drew

 

[Enablingwolf]

The magnifying lenses are not for seeing bad. They are a tool. It brings the work closer and allows you to see more detail. Really handy for small details. I have (progressive) bifocals. Which mag on the bottom, but I take them off so I can use the cheater lenses. Plus having the ability to see much closer (via magnification) is nice.

Also, the paper bag trick. It works for holding flux and such well. Just figure out f dry/wet is what you need at the time. What size pieces work for you and such. I like 4"x4" pieces and can layer them if I use them wet. Or single like a dry flux wipe. Though I do admit, I used 6x6 before. Size is up to you. I still have a sort of a tube I made that acts like a flux dabber.. Rolled up a bag tightly and dip and dab with it. I do have a few size brushes though. Sometimes I like spot treating things or pushing the flux around specifically. Heck even adding it hot.

The 3^rd hand tool is ok for specific applications. Most the time I use it for wiring joints. I used the lens only once or twice since I got it. I usually keep it off the tool. I does get in the way. If I need it on the tool. I just attach it again. Since i have cheaters, it does not go on often.

 

[Drew@PSU]

Zzzzzt! Back to life thread!

I'm giving one last try this weekend, picking up a new tip for the RS iron and see if I can't get anything to happen before I package it back up and recycle it.

I got some tip tinner/cleaner, I've got only the vaguest idea on how to use it. Heat iron up, dip in cleaner (powder), clean off on sponge?

I scraped the connection I was trying to desolder with a dental pick to make sure it was clean and free of dirt and such, to no avail.

While I hate to give up on stuff that's relatively straightforward (so I thought), I'm reaching the point of having spent too much trying to fix this LCD.
More to follow tomorrow.
-Drew

 

[xtkxhom3r]

Zzzzzt! Back to life thread!

I'm giving one last try this weekend, picking up a new tip for the RS iron and see if I can't get anything to happen before I package it back up and recycle it.

I got some tip tinner/cleaner, I've got only the vaguest idea on how to use it. Heat iron up, dip in cleaner (powder), clean off on sponge?

I scraped the connection I was trying to desolder with a dental pick to make sure it was clean and free of dirt and such, to no avail.

While I hate to give up on stuff that's relatively straightforward (so I thought), I'm reaching the point of having spent too much trying to fix this LCD.
More to follow tomorrow.
-Drew

if you live in San antonio, tx you can bring it by im sure we can get it done

 

[kayson]

On thick PCB's with lots of copper, you sometimes need a ton of heat to get the solder to melt. I did a lot of PCB soldering work at my internship over the summer, and sometimes I'd have to put the pcb under the heat gun, and hold the iron on it for 30-45 seconds before the solder even started to melt. Obviously make sure you've tinned the iron, and flux will help, but use the biggest tip you can find and the highest temperature. Just be careful not to burn the board! Desoldering is always a royal PITA..

 

[Drew@PSU]

Haha! Success! Or at least, the illusion of success for now. I went to Radio Shack and got a whole new iron (25W) and managed to get it tinned and cleaned first shot with the tinner/cleaner powder. Got all of the caps off and changed, hopefully I didn't break anything on the PCB. I'm going to put it back together in a little bit and see if it works.

xtkxhom3r - Nope, sorry, Texas is a bit of a drive, lol. Thanks for the offer though.

kayson - Yeah, it did require a bit of heat. I had to hold the iron to it for about 30 seconds like you said. The caps I took off were quite warm, but I think I found the busted one. Unless it was me pulling it off too forcefully. Either way, it's off. I throw up a pic of it a little later.

-Drew

 

[xtkxhom3r]

haha awesome man!! glad you got it done i told ya it can be done

hopefully the screen works if not then look at the bright side now u have a few more soldering tricks up your sleeve

 

[Drew@PSU]

Perseverance FTW! It looks just fine, gonna run through the range of power states ( since that was what went bad ) and make sure everything works. I am excite!

A big thanks to everyone on OCF who helped out with tips and encouragement!
-Drew