Computer Related > Solder mobile repair Computing Issues
Thread Author: sooty123 Replies: 18

 Solder mobile repair - sooty123
I need to replace the c port charger on my phone. I've just a soldering iron to try and heat (what I think is) the solder however not much happened.

I watched this video and at 9.30 he puts some sort of flux on it. Does anyone know what type of flux it is and if using a soldering iron* for heat would work ?

*I've not got a heat gun but they seem to be used quite a bit on CB repairs on YT
 Solder mobile repair - Kevin
The flux is to remove oxidation and help the solder 'flow'.

A soldering iron isn't going to do the job for you. The USB socket in that video is surface mounted which means that the fiddly little soldered joints are underneath the socket, between itself and the PCB. You need to be able to get all the joints molten at the same time to lift the socket from the PCB.
Also, nothing is happening when you use a soldering iron because your soldering iron doesn't have enough oomph to melt the joints before the metal part of the socket has transferred all the heat away. If you use a soldering iron with more oomph it's likely that the localised heat will knacker the PCB anyway.

I'm pretty good with a soldering iron and wouldn't attempt that job without a heat gun.

Your only other option is to carefully butcher the broken socket until you can get to the joints underneath. You then have the problem of soldering in the new socket. Even if you have a heat gun, aligning the new socket with the solder pads underneath where you can't see them won't be easy.
 Solder mobile repair - sooty123
Thanks, I've done a few bits and bobs of soldering but it was quite a while ago, I figured I must have been missing something.

I thought it'd give it a whirl, I'd rather repair than chuck stuff. I've done a few phone and tablet repairs and no problems but this one is a bit trickier.

I did think about just bodging it off but too high a risk of damaging the pcb.
 Solder mobile repair - VxFan
Any "repair" cafe's in your local area.

A couple have sprung up in nearby towns to me that meet up monthly and help people to either DIY repair anything from putting in a new zip in a pair of jeans to repairing small electrical goods, or have someone who will do it for you. Any money made gets puts back into the community, helps the food bank, homeless, etc.
Last edited by: VxFan on Wed 17 May 23 at 14:22
 Solder mobile repair - sooty123
>> Any "repair" cafe's in your local area.

No I'm afraid not.

I did ring up a couple of phone repair shops. one was a flat no the other err maybe but it would need to be sent away.
Last edited by: sooty123 on Wed 17 May 23 at 14:38
 Solder mobile repair - Fullchat
Isnt it possible to heat up the individual joint and use one of those instant vacuum things that come with soldering iron kits to suck away the molten solder?
 Solder mobile repair - tyrednemotional
...a (de-)solder pump. Pretty near essential for removing components with multiple solder points....
 Solder mobile repair - sooty123

This one seems a bit more straight fwd, any ideas what type of flux is best for this job?

Would this work?
 Solder mobile repair - bathtub tom
I've used de-soldering braid before:
It just sucks up the molten solder.
 Solder mobile repair - sooty123
I'll order one of those braid kits cheers.
 Solder mobile repair - Kevin
De-soldering braid is pretty useless on miniature solder pads unless you've made a real cockup and used too much solder in the first place.
In your second video what he's doing when he's removed the socket and is swiping the solder pads with the soldering iron tip is removing the extra solder that's deposited when the socket was first soldered to the PCB. He then swipes a bit more off, along with the old flux, with a cotton bud. Ideally he'd like to get ALL the old solder off and get back to an unsoldered copper pad but that's impossible. Too much solder and it will bridge from one pad to another and short things out.
The solder for the joint is actually already deposited on the new USB socket connections so all that's necessary is to apply a bit of flux to the PCB pads, place the socket on the PCB so the connections are touching the pads and apply enough heat to melt the solder but not enough to affect other nearby components or damage the PCB.

Do NOT use the flux in your link. Plumbing flux is corrosive to electronic components, you need flux made specifically for soldering electonic gear.
Last edited by: Kevin on Wed 17 May 23 at 17:32
 Solder mobile repair - sooty123
Too much solder and it will bridge from one pad to another and short things out.

Good point kevin, they are really small.
 Solder mobile repair - VxFan
Can't remember the last time I used flux for soldering (other than for brass plumbing joints).

Solder should already come with the flux in it. Unless it's the modern carp that doesn't even have lead in it anymore.

I've also found solder braid useless for most applications. A solder sucker works better providing you keep the hole clear of solder debris.
 Solder mobile repair - sherlock47
Do people not read what Kevin said? It is a surface mounted device - braid - solder with flux etc are really not relevant. Solder paste and heat gun is the way to go!
 Solder mobile repair - zippy
I have a client that makes small batches electronic circuits. They purchased a surface mount machine from a high electronics manufacturer that had a range of mobile phones when they pulled out of the market when smart phones arrived and they saw that they couldn't compete with Apple.

They also repair other companies boards and have a team of dexterous people who can fix faults on surface mount boards.

When asking about the cost I was surprised of the figures quoted, sometimes a couple of thousand pounds to fix a board! I did ask what the rationale was to their customer and the comment was the boards they tend to fix contain components that can cost tens of thousands so it's well worth attempting repairs.

My mate is the lead electronics engineer in a company that plays with lasers. All his work is circuit design software which he converts to "breadboards" to see if they work before the design is sent off for prototyping.
 Solder mobile repair - Zero
I am s*** hot with a soldering iron* having been taught by an expert when I were a young avionics apprentice.

Solder braid does have it uses in certain circumstances, you need to flux the braid first. A solder sucker is better of course. The secret tho is not to lump too much solder on there in the first place. Luckily I have a (dwindling) supply of lead based solder, (one reel very fine gauge) and a good flux (apply minimum amounts with a cocktail stick) I have fixed USB sockets on many a tablet/pc board with my hot air gun.

I am steeling myself to take my Sony Video camera apart to see if I can fix that. Now that is an exercise in many fiddly screws and interesting connectors..........
 Solder mobile repair - Kevin
I wish you luck. I took Mrs K's holiday camera (an Olympus Tough) apart to try and fix a dodgy zoom motor. Not a chance - it's based around a couple of custom ASICs that make a millipede look deficient in the limb dept.
 Solder mobile repair - Zero
not entering this adventure under a fog of hope or expectation,
 Solder mobile repair - sooty123
Anyway to put an ending to this, if anyone is remotely interested, found someone that would repair it. Done in about 30 mins or.

Noted about the braiding, I'll keep the stuff i bought I'm sure it'll come in handy for the next tablet/phone that needs repairing.
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