soldering micro components

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macuser

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#177641 10-Aug-2015 12:10

So I managed to water damage my G Watch R by accidentally putting a pin hole through my barometer hole which I thought was a reset button and filling it with sweat from my gym routine.

It's really not doing well and the display flex cable has a bunch of components that are so corroded that the solder is eaten through. You can't buy replacement OLED panels off ebay, and I don't want to send it for official repair because it cost me $160 from Warehouse Stationary.

I was hoping that I could use a reflow solder hot air gun to reattach the components. The watch boots and the screen turns on...but turns off pretty soon after.

Possible? You can see the damage here (this was after a bit of cleaning, and the component which has now come clean off)

SepticSceptic

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#1364761 12-Aug-2015 16:54

You could probably do it with a very fine point soldering iron. I have used a 15w iron for this kind of work, though I cant seem to find an equivalent. Something like:
http://nz.rs-online.com/web/p/soldering-irons/2589044/

There is a bit of an art to it. Tin and tack one end so it's in place, solder other side, and then go back and solder the first joint.

I suspect that the damage could be more .. corrosion under the existing components, corroded pcb tracks, and that's assuming the components themselves haven't been damaged

macuser

2120 posts

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#1364764 12-Aug-2015 17:01

Are those de-soldering heat guns so bad?

I would be absolutely terrible at doing this with a soldering iron, but the de soldering guns make it look easy with the flux paste. The components are only a couple mm long.

What do you think it would cost to have this work done by an expert?

SepticSceptic

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#1364786 12-Aug-2015 17:41

Yes, there is always the hot-air gun soldering tool - with a very fine nozzle to localise the hot air to melt the solder paste / flux. Unless you've had practice it's probably even harder to use and not melt anything else :-), but that's just my opinion ..

Because of the corrosion, I think any sane repairer wouldn't touch it, because there is no guarantee that just replacing the components is going to fix it, and you'd be down several ten's of $$, and may even possibly fail again shortly after. Corrosion means some voltage / current flow, and will possibly lead to damage elsewhere, usually unseen. Been there, done that.

Even after soldering, there's usually conformal coating, or something to keep the moisture at bay.

Personally, I wouldn't touch it, unless it was mine, and not care if it was damaged further. Wouldn't do it for money, friends or family.

Ideally, $160 is not big money if they are going to replace the entire damaged module, and also have your barometer fixed ....

1101

3122 posts

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#1365348 13-Aug-2015 10:26

You may have also damadged the copper tracks on the board. Sort of looks like it but hardto tell from the photo.
They can tear off quite easily with the component , and dont like continual overheating with soldering irons

graemeh

2078 posts

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#1365389 13-Aug-2015 11:04

If you are in Wellington I have the gear to do this. I won't touch it myself for the reasons others have given but you're welcome to use the gear.

If you haven't already I suggest you use a good strong magnifier (10x at least) and have a very close look at the damage.

macuser

2120 posts

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#1365620 13-Aug-2015 14:58

graemeh: If you are in Wellington I have the gear to do this. I won't touch it myself for the reasons others have given but you're welcome to use the gear.

If you haven't already I suggest you use a good strong magnifier (10x at least) and have a very close look at the damage.

Hey mate!

I appreciate the offer, I am located in Auckland though so won't be able to take you up on your offer.

graemeh

2078 posts

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#1365632 13-Aug-2015 15:05

macuser:
graemeh: If you are in Wellington I have the gear to do this. I won't touch it myself for the reasons others have given but you're welcome to use the gear.

If you haven't already I suggest you use a good strong magnifier (10x at least) and have a very close look at the damage.

Hey mate! I appreciate the offer, I am located in Auckland though so won't be able to take you up on your offer.

That's a shame. There are plenty of tutorials on Youtube about soldering surface mount components. The ones from EEV Blog and Spark Fun are very good. If you decide to go ahead and try it is probably best to use a fine tipped soldering iron. Send me a PM with your address if you want me to post you some solder to try with. I've got some that is .46mm which is quite good for that sort of work.

Also the existing solder is likely to be lead free so it really helps to put some leaded solder on it first as the lead free has a much higher melting point.

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SepticSceptic

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#1366092 14-Aug-2015 09:27

Quite happy to lend you my fine-tipped iron, though I don't have any solder paste / lead free solder - I'm in Auckland ..
If you are able to, pick up a couple of SMD parts and a small piece of Vero strip board ( PCB with copper strips and a grid of holes), and have a bit of a practice before starting on your watch.

graemeh

2078 posts

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#1366110 14-Aug-2015 09:45

SepticSceptic: Quite happy to lend you my fine-tipped iron, though I don't have any solder paste / lead free solder - I'm in Auckland ..
If you are able to, pick up a couple of SMD parts and a small piece of Vero strip board ( PCB with copper strips and a grid of holes), and have a bit of a practice before starting on your watch.

If OP gets me to send him some solder I can throw in a few blank scrap PCBs and some components to practice soldering on.