how do i recap mobo with only soldering iron

[coolcurrent]

hello guys
i want to recap my Compaq evo d510 mobo. all i have isa 6w soldering iron. i have already made attempt but the capacitor won't desolder properly as the are soldered both ways.

can you give some help on what to change and the ways i can use to delsolder them?

[dood]

Re: how do i recap mobo with only soldering iron

A 6w soldering iron likely won't be enough, but you can try... I remove caps by heating one leg at a time and working them out a little bit at a time. Same way for putting new caps in. I don't completely desolder or clean the holes.

You will also need some solder to add to the holes once you get the new ones in.

[lmcancu]

Re: how do i recap mobo with only soldering iron

You will need at least a 40 W iron.

[coolcurrent]

Re: how do i recap mobo with only soldering iron

sorry i meant a 60W.

the technique or removing and replacing them is what i really want to know.
can you share your style or doing it thanks

[lmcancu]

Re: how do i recap mobo with only soldering iron

A 60 W iron should definitely be enough. What do you mean by soldered both ways? Search the forum here. There are alot of posts about recapping techniques. Also on the badcaps site there is a tutorial as well. I've only capped about 3 boards myself (and only a few capacitors on each) and found it to be relatively simple. The one technique I use is to apply fresh solder on the leads. This helps with getting heat into the area you need. I do one lead at a time and gently wiggle the cap from the other side until the leg comes out. On one board, I didn't clean the hole and wiggled the new cap back in. On the other boards I cleaned the holes. Note, for the first leg it can take several seconds for the solder to melt since the board will absorb some of the heat. A good iron is also very important, make sure its clean, and has a stub end rather than a point as the heat transfer is better. Make sure to tin your iron before and after.

[shovenose]

Re: how do i recap mobo with only soldering iron

i think its called a chisel tip not a "stub" tip.

but i dont understand the obsession with cleaning the holes. i dont do it and its never been a problem. but then again ive only worked on power supplies not motherboards

[PCBONEZ]

Re: how do i recap mobo with only soldering iron

i dont do it and its never been a problem. but then again ive only worked on power supplies not motherboards

On mobos when you free the cap the holes are often left full of solder which prevents inserting the legs on the new cap.
Since the holes tend to be smaller diameter and longer [due to thick PCB] on mobos it isn't always easy to clear the solder from the holes.
.

[momaka]

Re: how do i recap mobo with only soldering iron

the technique or removing and replacing them is what i really want to know.
can you share your style or doing it thanks

This is how I normally do it:
https://www.badcaps.net/forum/showpo...7&postcount=23

As far as soldering irons, I've used a 30W to remove capacitors on a motherboard in the non-vrm area. It was fairly easy. Cleaning the holes was the harder part. Normally I use a sewing needle or a pin of some sort to clean the holes by heating each hole and pushing on the other side with the needle/pin.

[PCBONEZ]

Re: how do i recap mobo with only soldering iron

sorry i meant a 60W.

the technique or removing and replacing them is what i really want to know.
can you share your style or doing it thanks

With minimal tools....

Step 1: MAKE A CAP MAP showing polarity, uF and volts for all caps you will touch.

Once that is done:
-
Alternately heat the cap leads as you gently 'rock' the cap out a little at a time.
[Don't use a bunch of force. The holes are plated on the inside [this is called a via] and that plating makes connections with traces between PCB layers. If you yank out a via the board may become useless junk.]
-
When you get the cap out mop up the old solder and try to clear the hole with some *fluxed* solder braid [solder wick].
-
If hole doesn't clear use a Stainless Steel needle chucked into an ALL METAL Exacto knife handle and heat solder side of board while [gently] working the needle in from the other side. [Lightly rotate-spin, don't push hard.]
When needle is far enough through to accommodate a cap lead [usually leaving the needle in] clean up the excess solder you pushed out so it doesn't follow the needle back into the hole.
[Next part depends on what the solder that came out did as in the shape it took and did it stick to the needle. Kind'a have to size it up and decide what to do]
Might be able to just remove the needle and clip off the solder if it took a rope shape and didn't stick.
Might have to use some wick with the needle still in if a big blob came out or the needle stuck.
[If needle is stuck bad.]
Heat *the needle* from solder side and gently rotate it until you know it is free and remove it.
If solder goes back in the hole as it sometimes does you will have to start over but usually the second time is easier and gets it done.
-
Should have a clear hole now.
Clean up the area with some isopropyl alcohol. [Wet Q-tips or tooth brush.]
-
Installing the new caps is about the same here as anywhere else.

- - -
Want electronics fluxed solder about .020-.022 diameter.
60/40 or 63/37 or similar.
Don't get lead free type.
Lead Free is not really required for repairs it makes the work harder.

ALL Metal Exacto handles [not the ones with the plastic chuck] can be found at Home Depot or hobby/craft stores like Michaels.

Want fluxed solder braid w/size color code green or blue.
[I like green best for mobo work but that's just me.]
Tip: Loosen the braid in the section you will use a little bit before you use it. It tends to pull tight when you pull it off the spool and that closes up all the little air gaps where the capillary action is supposed to occur.

You can get Copper or Stainless Steel scrubbies [look like very coarse steel wool] about anywhere that sells dish soap. In conjunction with the typical sponge, it helps in cleaning up tips.
You can be creative an make your own holder for it. A small 4 oz can nailed or screwed to a board [for the weight so it stays put] with the can edges folded in to grasp the scrubby isn't very pretty but it works fine.
.

Might sound overwhelming at this point but it really isn't all that hard to recap a mobo.
Just takes attention to detail and patience.
Don't try to hurry it up. If you are going to screw up that's when you will.
If you get frustrated set it down for a while and come back later.
.

[coolcurrent]

Re: how do i recap mobo with only soldering iron

i recap the caps close to my processor, but my problem still persist.
my mobo does not power, it just shows the two green led green with processor and psu fan spinning constantly.
no video, no sound

how do i trouble shoot this problem now?

[gerg]

Re: how do i recap mobo with only soldering iron

normally when i recap a board i will replace all of the capacitors such as if one is blown then i will replace all of them that are that size on the board. I don't have an ESR tester to find out if the caps are still good or not yet i just go on the principle better safe then sorry.

[lmcancu]

Re: how do i recap mobo with only soldering iron

Can you provide a pciture of your motherboard? Did you replace at least all of the caps that are bloated?

[PCBONEZ]

Re: how do i recap mobo with only soldering iron

Inspect your PSU for bad caps.
Check chipset and MOSFETs for cracks or melted spots. [Might just be shiny spots.]
- Should have done this first but you are new.

Then if you find nothing list all your caps here and someone can tell you if any are problem caps.
Need: Series, uF, Volts, diameter, and sometimes length.
.

[coolcurrent]

Re: how do i recap mobo with only soldering iron

I recap some capacitors not all, the reason being that i cant find the same small diameter of my board capacitors.

The capacitor i replaced are the once close to the processor power.

I will take a snap with my phone and post it here tomorrow.

the ones i get is albeit wider in diameter, and so will not fir on the board properly as the capacitors are tightly packed near the processor