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need advice on soldering on my n800!
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xxM5xx
2008-09-13 , 08:48
Posts: 354 | Thanked: 93 times | Joined on Oct 2007 @ New York
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If you are nervous about doing it, I can do it for you. I do this sort of thing all the time.
It is good that you took excellent photos of the PCB, I can see there is no visible signs the board has any physical damage yet. Looks like your solder is just torn free.
The key to doing this is having the correct tools and the experience. You definitely do NOT want to use too much heat.
I'm not looking to make any money, just offering to help out a fellow member of this community. Let me know.
Regards,
M5
Note: The best tool to do this is a reflow, hot air tool on the data pins. It can be done with a 25-30 watt pencil soldering iron also, but that would be my second choice for doing the pins should you not have access to a hot air soldering tool. The four pads on the corners will need a soldering iron because the USB metal housing will suck heat away too quickly to use hot air. You'll want to remove the old solder on all the pads first, then tin the pads with fresh solder (preferably silver solder), then align the connector and reflow the solder that was put down during the tinning process. Do not overheat the substrate. Afterwards, wash the solder's flux away with a solvent and blow it dry with compressed air or nitrogen. If you used rosin fluxed solder (instead ofwater soluble flux), the common solvent choices are Toluene, Methanol or Chlorinated Brake Parts Cleaner. Use a disposable toothbrush on the area after wetting it with solvent. Immediately blow it dry before the solvent dries on it's own. Repeat the washing and compressed blow drying until the board area looks spotless.
From the looks of your pictures, the factory soldering on the four corners could have been better, which is why the connector broke free when pulled on. It is a common defect with SMT electronics when small parts and large metallic connectors are mixed on a substrate and passed through a tunnel furnace. The engineers fear a profile that is too hot, and error on the side of too cool, and you see this result. The real solution is to hand solder the four anchor corners AFTER the board exits the tunnel furnace but the extra step adds labor costs, and so it gets bypassed frequently.
This is a huge problem in the laptop computer industry where the power connector is attached to the motherboards. All the factories need to do is hand solder that section, but most of them don't and you get end-users with loose power connectors later on. It is a manufacturing defect that doesn't reveal itself until long after the product has left the factory. I have fixed close to a hundred of them.
If you do it yourself. I hope it works out. Regards.
Last edited by xxM5xx; 2008-09-13 at
09:15
. Reason: added the reflow hot air comment
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