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Warning about soldering tiny components.

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[email protected]

Inactive Moderator
Joined
Sep 27, 2003
Warning About Soldering, Especially Tiny Components

Alright, I have known this for a long time, but I guess I shouldn't have been so stupid to not take my precautions. I used to do a lot of soldering at my old job, and have had the solder points come off, but I usually figured a way around by following the trace and finding another point to solder to.

The problem with computer components is that it's so crammed that it is hard to find a new soldering point, and even if you do, you don't know if it's going to go in parallel with another component and cause even more damage.

Here is what happened to me:

I killed my 9500np trying the hardmod. When I was getting ready to take the stock heatsink off, one of the caps from the back of the card must have "fallen off", literally. You can tell it fell off b/c the solder point looked dried out, and not forced off.

Sidenote: I've seen this happen plenty, as I'm sure most of you others have as well. It's not always the users fault. Since these boards have to go through ovens for mass production, they have to have solder paste pasted onto the entire PCB before the components are put on. Sometimes the paste may be off by a micrometer, and sometimes it's not enough.

Alright, so I used my $8 soldering iron to try to fix the cap back on last week, and soldered it back on. I never tested it after, like an idiot. ALWAYS TEST ANY NEW WORK THAT YOU HAVE DONE TO A PIECE OF HARDWARE TO RULE IT OUT WHEN YOU LOOK AT THE BIG PICTURE!!! This was probably my big mistake... read on...

I then removed the stock heatsink and the shim, and tried the hardmod to the card with the $8 iron, and the F-ing thing was too thick of an iron to solder the tiny points. It just kept melting the entire are of solder where the 3 solder points were... basically, I wanted to solder a resistor from points 1-2, to points 2-3, but points 1, 2, and 3 kept heating up. The resistor that was where the hardmod point was (position 1-2) ended up sticking to the iron and coming off. I then left everything and said "I'll wait for my Hakko936 to arrive." (The Hakko 936 -12 ESD is a very nice soldering station. Google it if you don't know what I'm speaking about)

I took the little resistor that fell off and placed it by the card (it's REALLLLLLLLLY small just to let you know, especially when you see it off of the GPU). I got the Hakko set up and warmed up, and then couldn't find the resistor that came off the hardmod points. It may have stuck to my hand and then flew off, who knows. I didn't think I needed it anyway, as I believe it was just a jumper. I did the hardmod by soldering points 2-3, put the heatsink back on, hooked it up and artifact galore!

I figured it was the nasty soldering job with the $8 iron on the cap that had fallen off, so I desoldered the cap off, and tried the card without the cap... same artifacts. I then undid my hardmod, and soldered back the initial 9500np soldering points... instead now it wasn't a resistor in that spot since it was gone, and so it was just a solder jumper on points 1-2. Card still had same artifacts.

I then tried soldering the cap back on to the back of the card, and it now just looks even nastier... It became a really nasty soldering job because I believe that the soldering point came off... tried the card again, and still artifacting the same way.

I think what happened is that the solder contact on the PCB itself must have fallen off... this used to happen a lot at my old job when we soldered parts onto the audio interfaces. sometimes the metal piece that is connected to the traces comes out... that's pretty much your solder point. When you create too much heat, the piece of metal heats up and pops off. It loves to stick to the iron, so a cheapo iron really is your worst enemy when you're soldering FINE POINTS. When this happens, you're usually screwed cuz you then have to hope that you can solder the electronic component to the actual TRACES, which is TOUGH to do, especially with a cheapo iron. In my case I had a Hakko936, and it took so long to get the cap to stick back on, but as you can see... the card is still artifacting, so now who knows the cause...

I can guarantee that the $8 iron was the cause. Either it heated up the GPU PCB (green area around the actual GPU die) too much, or it heated up the PCB on the back of the card where the cap was...

Now I don't know if the problem is by the hardmod, or if it's the cap that fell off... this is the situation that I created for myself by not taking my own precautions.

I didn't use flux at all with the $8 iron cuz I didn't have any, but I did use plenty of flux when working with the Hakko.

Precautions:
  1. USE FLUX AT ALL TIMES IF YOU HAVE IT, IN ORDER TO ENSURE A CLEAN JOB! DO NOT USE TOO MUCH, AS WARRIOR STATED IN POST #4.
  2. TRY NOT TO USE A REALLY CHEAP IRON ON TIGHT SPOTS, AS A CHEAP IRON IS USUALLY TOO THICK.
  3. TEST OUT COMPONENTS FOR EVERY CHANGE YOU MAKE WHEN POSSIBLE. IF IT TAKES YOU 5 MIN TO TEST IT, IT'S BETTER TO BE SAFE THAN SORRY.
  4. DO NOT HOLD YOUR SOLDERING IRON ON THE SAME SPOT FOR A LONG PERIOD OF TIME BECAUSE IT CAN AND WILL RUIN SOMETHING. THIS CAN CAUSE DAMAGE TO THE PCB, OTHER SOLDER POINTS, AND WORST CASE IS THAT THE METAL PIECE INSIDE THE SOLDER POINT MAY STICK TO YOUR IRON AND COME OFF!!
  5. IF YOU DO USE A CHEAP IRON, YOU CAN ALWAYS FILE IT DOWN TO A FINER POINT, OR BUY SEPARATE TIPS FOR IT

I have got to say, IMO, #4 is the worst thing that can happen, next to a physically broken component. When the metal piece comes out, you'll know what I'm talking about. Nothing angers me more because that is something that is only caused by being sloppy.

Don't be afraid to PM, EMAIL, or AIM me with questions, or request additions.

I may neaten up this post as time goes on. I made this post to keep others from destroying their hardware.

Special Thanks to:
RoadWarrior
 
Last edited:

RoadWarrior

Senior Member
Joined
Nov 25, 2001
Location
Niagara Falls, Ontario, Canada
Heh, well I kinda approach things from a different direction. I've broken too many "good" irons now, well mid range ones I guess, never ponied up $100+ for one. I get the real cheapies, and file the tips to different shapes according to the job I'm trying to do. It costs less than buying a selection of tips for a "good" iron. Also you can have two or three different tips "hot" at the same time and switch from one to another. Then you don't fall into the trap of doing something too small with the big tip, or too big with the small tip because you can't be bothered waiting half an hour for the iron to cool off, fit the smaller tip, wait for it to warm up again....

Another good idea with working on small components is to get some low melting point solder, 200-220C, because as you noted, boards are solder flowed in ovens, these ovens use solder at 200-220C and thus components are designed to survive these temps. Using "regular" solder, which is usually melting at 240C up, is practically asking for trouble.

Flux can be a mixed blessing also, it will eat away at the adhesive bond holding PCB pads to the board, so if you get your pads swimming in flux, by the time you boil it all off with the iron, it will have eaten away the bond under the solder pad... So best idea is to use it sparingly on PCBs, only usually needed on dull bare copper, or on component leads.

my 0.02

Road Warrior
 
OP
g0dM@n

[email protected]

Inactive Moderator
Joined
Sep 27, 2003
RoadWarrior said:
Heh, well I kinda approach things from a different direction. I've broken too many "good" irons now, well mid range ones I guess, never ponied up $100+ for one. I get the real cheapies, and file the tips to different shapes according to the job I'm trying to do. It costs less than buying a selection of tips for a "good" iron. Also you can have two or three different tips "hot" at the same time and switch from one to another. Then you don't fall into the trap of doing something too small with the big tip, or too big with the small tip because you can't be bothered waiting half an hour for the iron to cool off, fit the smaller tip, wait for it to warm up again....

Another good idea with working on small components is to get some low melting point solder, 200-220C, because as you noted, boards are solder flowed in ovens, these ovens use solder at 200-220C and thus components are designed to survive these temps. Using "regular" solder, which is usually melting at 240C up, is practically asking for trouble.

Flux can be a mixed blessing also, it will eat away at the adhesive bond holding PCB pads to the board, so if you get your pads swimming in flux, by the time you boil it all off with the iron, it will have eaten away the bond under the solder pad... So best idea is to use it sparingly on PCBs, only usually needed on dull bare copper, or on component leads.

my 0.02

Road Warrior
So I should take out the flux warning completely you think?

By the way, I sanded down my $8 iron also... it just got tedious and I am happier with the Hakko. :)

Thanks for the awesome input.
 

RoadWarrior

Senior Member
Joined
Nov 25, 2001
Location
Niagara Falls, Ontario, Canada
Well, flux is good, because too much heat also destroys the pads as you said, and you can get a quicker cleaner joint by using it. There's just a balance between using some and using too much. It's like thermal paste, some is good, more isn't better.

Another thing to be aware of with modern components is a phenomenon known as popcorning. They are designed to survive a reflow oven, however, they are "baked out" for 8 hours or so first at a little under 100C to make sure they do not contain any moisture. The epoxy packaging of the components is very slightly porous and will suck up water from the atmosphere like a sponge. When this water is turned to steam by intense heating, resulting in high local pressures, the package will "popcorn" that is, blow up like a kernel of corn does. As one can imagine, this is baaaad mmmkay. Therefore, try not to heat components any longer than absolutely necessary when soldering, or this might happen.

If one has to replace mosfets, or other such components that might require quite a lot of heating to remove from the PCB or replace, and the board has been sitting a unused a few days. You can assume it has absorbed some atmospheric moisture, and it would be wise to place the board and replacement components inside a hot air heating duct for a few days (Providing you don't have a humidifier hooked to the furnace) and remove them only when you are ready to work on them. Thus the risk of popcorning while you're trying to solder them will be minimised. If you were doing something extreme like attempting to replace mosfets for ones rated for a higher wattage on a motherboard that is in service, you could just make sure you leave it running until you need to work on it, they get hot enough while working that they shouldn't pick up much moisture unless it's been off for a long while, though you should make some attempt to dry out your new parts. Mainly though if you were trashing the parts you were replacing, you'd be concerned only about neighbouring components on the board surviving, due to prolonged heating.

This isn't something you'll come across every time you do a voltmod, but it something to be aware of if you get into extensive board modding and repair.

Also remember this if you build a super potato cannon to put a mini-itx wireless server pod into low earth orbit, bake it out or the vacuum will popcorn everything :D

Road Warrior
 
OP
g0dM@n

[email protected]

Inactive Moderator
Joined
Sep 27, 2003
RoadWarrior said:
Also remember this if you build a super potato cannon to put a mini-itx wireless server pod into low earth orbit, bake it out or the vacuum will popcorn everything :D
You okay? :)

I'm making changes now...
 

CWynn

Member
Joined
Aug 1, 2005
Location
Batavia, IL
I've never had any problems with my 15w or 25w radioshack irons. I've had them for years and done various voltmods with each.
 
OP
g0dM@n

[email protected]

Inactive Moderator
Joined
Sep 27, 2003
CWynn said:
I've never had any problems with my 15w or 25w radioshack irons. I've had them for years and done various voltmods with each.
Well, my $8 iron wasn't too friendly to that cap. I didn't heat it up too much, nor did I use flux to blast that solder point, and it still got screwed up. :(
 

ƒÓÒl

Member
Joined
Aug 27, 2005
For my fine work, I found a stainless steel bolt that fits perfectly into the threaded end of my cheap iron. I then cut off the head and filed it to a pin point which works perfectly.

When removing a component, I always use melted solder. That is, I pick up a small ball of solder from my spool and use it as the hot point to rememelt the solder that holds the component. I find it conforms to the shape of the vict...er existing solder point and transfers heat much faster than just a hot iron tip. This keeps the heat concentrated to the area intended because it works so fast.

When soldering a component into place, I always clean the area first with acetone and a q-tip. There's often a fine film of conformal coating or even laquer on unsoldered areas, and this removes it.
I then add a tiny dot of organic cream flux with my blunt tip syringe.
Place the component, the flux helps hold it in place.
Then I pick up a ball of fresh solder on the tip of the iron to solder the component in place.
Clean off the flux afterwards using alcohol on a q-tip...always. If left, it will corrode the join.
This makes soldering acurate and very fast. Heating other components or melting traces never happens with this method because it's over very quickly (less than a second). Never ever ever use the tip of the iron to preheat an area and then add solder, that method is for TIG welding and should remain so.

Use a wet sponge to clean your tip everytime you place it back in the holder, and everytime before picking up fresh solder. Everytime. Dirty tips can lead to the same symptoms as a cold joint (ie, bad spread/wetting, and poor adhesion).

Just some tips from an ex-pro.