need help soldering power adapter on motherboard

10/02/2006 09:08:29 AM · #1

I'm attempting to build one of those digital photo frames using an old laptop I had laying around. I've dismantled everything and should be ready to mount it all in a frame, but the stupid power jack on the motherboard is broken and needs to be replaced. I've found the replacement part on ebay for about $5, but it needs to be soldered to the mobo to work, and I've never really done anything like this before. Can anyone offer some pointers/advice?

Also would like to relocate the power switch, but I believe this requires more soldering. Again, anyone with experience doing this?

Thanks!

10/02/2006 09:35:15 AM · #2

Soldering just takes a bit of practice. I don't know what kind of adapter you are talking about, but I'm assuming it's farily large and easy to solder.

Do you have a soldering iron and solder?

Just twist the wires that need to be soldered together, and apply some solder across the joint to create a good electrical and mechanical connection. Make sure you cover any open conductors up with insulation tape to prevent shorts.

I would be able to help better with more specific questions and information about the component that needs to be soldered.

10/02/2006 09:44:55 AM · #3

Don't breathe in the fumes created from the flux burning off. Also make sure that you work on an old piece of cardboard (or something similar), to prevent and damage to your table. If you are not very careful to avoid touching any metal part of the soldering iron while it is on, you will learn the hard way.

Canon EF-S 10-22mm f/3.5-4.5 USM

10/02/2006 09:55:05 AM · #4

the piece that needs to be replaced on the motherboard is the AC adapter plug where the power cord goes into the laptop. it shattered into a few pieces and the one of the prongs that connects to the mobo snapped off.

seems like i need to desolder the existing piece that's on there before adding the new piece.

Any ideas on how to attach wires and a new power switch, so i can 'relocate' the existing on/off button?

Also, can you recommend what equipment i'll need? I read that a small, 30w soldering iron would be good, but what else? Going to head to radioshack this week and would like to get everything in one shot.

Message edited by author 2006-10-02 09:56:05.

srdanz

Canon EOS-5D Mark IV

10/02/2006 10:01:27 AM · #5

You have a digicam, give us a photo of what you' want to do.. picture is worth a 1000 words.

One thing you may consider buying (or borrowing from someone if you'r enot going to do this for a living) is a solder sucker. This would help you not have loose solder all over the place (it is conductive so you may not want that).

Also, make sure you practice on an old, cheap handheld radio or something before soldering on the motherboard. Make sure you gauge how much time you need to apply the heat to liquify the solder. Excessive heat can and will damage surrounding ICs, and there is more than likely to be some in vicinity. Even ordinary capacitors/resistors can be screwed up by excess heat. So, get in, do the job as fast as you can, get out. If it does not work at first, let it cool down some before trying again.

Hope this helps some.

10/02/2006 10:13:22 AM · #6

Originally posted by srdanz:

A photo will definitely help. If the adapter is attached to the motherboard with wires, all you need to do is cut the broken adapter off and solder the new one on. If the adapter goes into a PCB, you will have to be more careful to not damage anything on the board, or let solder spill over the pads causing short circuits.

I found that copper braid works better than a solder sucker to remove excess solder. You can also get solder off of robust components by melting the solder and then quickly hitting the component on a table, don't try this on a motherboard though.

I also advise practicing a bit first.

You will need to get solder as well as a soldering iron. Make sure the soldering iron has a small tip for precision work, ones used for electrical wiring around the house are too big. Get copper braid if you want to.

Sigma 18-200mm f/3.5-6.3 DC OS for Canon

10/02/2006 10:21:46 AM · #7

thanks guys. I'll snap some pics this week and post them. The parts are at my fiance's house so I might not be able to post until later this week.

Thanks again!

ElGordo

Canon EOS-400D Rebel XTi

10/02/2006 10:30:23 AM · #8

A 30 watt iron is adequate but can get much hotter than is necesary for electronic soldering. Ideal temperature is between 600 and 700 degrees F. Buy 'Eutectic Alloy' solder to avoid 'cold' solder joints. Keep in mind that the motherboard is a multilayer board with (potentially) more than one layer carrying power to various parts of the board, so it may take 10s of seconds to bring all the layers up to solder melt temperatures. Buy some non-corrosive soldering flux to aid in solder 'wetting'(rosin core solder may be adequate and rosin is the safest type flux to use). Apply the flux to the part's pins and to the motherboard, but apply sparingly. Buy some 'solderwick' to wick solder out of the motherboard solder pads after the old part is removed. Take great care when applying heat to the solder pads; they can de-laminate easily and fall off. Keep a wet paper towel near the iron to wipe excess solder and dross from the tip of the iron everytime you use it; this also helps to keep the tip temperature down. Good luck.

10/02/2006 11:02:15 AM · #9

ugh, the more i read the more complicated this is becoming. Can you briefly explain what the flux is for?

Again, I'll try to get a pic or two so this all makes more sense to everyone.

Thanks,
Mike

Originally posted by ElGordo:

Canon RF 24-70mm f/2.8 L IS

10/02/2006 11:22:10 AM · #10

Flux cleanes off oxides that form on the lead/tin mixture of the solder, helps the solder to stick better to metal. I've never used extra flux, only what comes in the solder core.

kirbic

Canon EOS R5

10/02/2006 12:37:44 PM · #11

Best thing is to go to Radio Shack and get solder intneded for electronics use. It contains a flux "core" inside the solder that is safe to leave on. Most fluxes sold for non-electronics use will cause corrosion if left in place.
Radio shack should (iI think) also sell "desoldering braid", which is a copper braid that you use to wick up excess solder. You'll need some of this. You'll also need a soldering iron intended for electronics use. Large, high-0heat irons intneded for soldering metals will overheat and permanently damage the board.
Here's how you should proceed:
- If possible, cut the leads on the connector at the top side of the board (connector side).
- Use the desoldering braid to wick out as much solder as possible from the holes. Work from the bottom side of the board (opposite from side where connector is mounted). Sandwich the braid between the iron tip and the solder joint. Move to a new spot on the braid for each joint.
- After desoldering, follow step (a) if you were able to cut the leads, or (b) if not:
a.) Briefly heat each location and pull out the remaining connector lead from the hole using a tweezers or needle-nose pliers.
b.) You should be able to get the connector free by heating each joint briefly and wiggling the connector upward. Be careful here! Don't apply much force, and don't try to get all the leads hot enough to melt the solder at once, or you'll risk burning the board material. Heat one joint, lift a bit, repeat on each joint until connector comes out.
- Once the old connector is out, the new one *should* go in without trouble. If not, you may have to make one more pass with the desoldering braid if there is solder blocking a hole. Also try briefly heating that location. The connector may slip thru.
- Once the new connector is in place, melt a bit of solder on the iron tip, place the tip on a joint and feed in a little solder wire until the hole is just filled. The entire process should take about 2-3 seconds, not much longer. Repeat for the other joints.
- Done.

10/02/2006 01:34:27 PM · #12

Thanks Kirbic. Awesome step-by-step walkthrough. Don't think I can cut the leads on the existing connector. It's hard to describe, but from what I could see, it appeared that all of the soldering was done on the bottom of the board, so hopefully i can easily remove the existing parts/solder.

I'll hit up the radio shack this week and see if I can pick everything up, then if I manage to get the busted piece out I'll go ahead and order replacement part!

Thanks again... great stuff. I'll let you know how it turns out!
-Mike

Originally posted by kirbic:

Message edited by author 2006-10-02 13:42:49.

10/06/2006 04:38:43 PM · #13

Copper braid will help you to remove the solder from the connector, otherwise you have to heat all the terminals at once and pull it out.

Canon EF 100-400mm f/4.5-5.6L IS

10/08/2006 11:54:09 AM · #14

Hey all...

Quick update:

I purchased a 15w grounded soldering iron from radio shack (designed for circuit board use), the desoldering braid, and some solder for electronics/circuits. Here's the problem -- i can't seem to remove the solder with the braid! I think something might be wrong with the soldering iron... I'll hold it directly on the solder and it won't even melt it...then, almost as if there's a certain spot on the iron that's hot, it'll melt, but even then the solder is only molten for as long as the iron it touching it. the braid won't work at all if i follow the directions (i.e. braid on top of solder i want to remove, hot iron on top of braid. It just will not melt the solder. is something wrong? do i need a higher wattage iron (the RS website says that this one, the 25w, and the 40w all go to the same temp, so I don't see why the iron would be the problem).

I tried adding some new solder to the joint i'm trying to remove, but that didn't help the braid do it's thing either. Like I said, it's really weird, but holding the hot iron (it was plugged in for about 10 mins) directly to the solder I was trying to remove, would only melt the solder about 1 in 15 tries, and even then it wasn't enough to allow me to get the desoldering braid in there to wick up the molten solder i wanted to remove.

Thoughts???

awpollard

Canon EOS-5D Mark II

10/08/2006 12:03:51 PM · #15

Had a bud who was with a the SDDSLR group who has since started a DSLR group in Hampton Roads Area...anyways I've been following his site and found he did a similar project Laptop to Photo Picture Frame Project he has jpgs of all the steps to took to complete the project.

Don't know if anything in there will help you or not but if anyone else is wondering how to do this it's a quick tut for the DIYers out there. I myself have four or five LTs at work that I have been wanting to do this same thing to.

Andy

kirbic

Canon EOS R5

Canon RF 24-70mm f/2.8 L IS

10/08/2006 12:29:19 PM · #16

The wattage of the iron is definitely one factor, and the other factor is heat transfer. The second factor is perhaps more important.
When you place the braid on top of the solder to be removed, then place the iron on top of the braid, the heat flows from the iron to the braid, thence to the solder. But the braid has a *very* high thermal conductivity and acts to wick heat away along it's length. You can't change the properties of the braid, but you can increase the heat transfer across the braid.
Tin the tip of the iron just before touching it to the braid. The solder on the iron will wet the braid, and provide a direct heat transfer path through the braid to the solder joint. This should speed melting of the solder in the joint.
If this doesn't work, it's possible that the iron just doesn't have enough wattage to do the trick