Strange WiFi problem on iPhone 3G after 3.0 update

Thank you Simple serve for your answer.

This guy reflowed in the oven and seems to be happy http://www.iphonetiquicia.com/repair-iphone-3g-wifi-oven/#comment-10

But I wouldn't take it for granted. Even oven temp and time are important. You're doing the job that expensive reflow ovens do. Don't just turn the knob and expect the oven to hit the right temp. Use an accurate thermometer and test your oven with it before you reflow.

Also, make sure you've done all your Apple trouble shooting first http://support.apple.com/kb/ts1559

Having several boards without wifi I tested the oven on one of them.... nothing better, wifi iis still out but the board works as before ....like with fridge before ;o)
If I have time I will try with higher tempêrature, nothing to lose.

please keep us updated 🙂

Alternatively, if you don't want to stick it in an oven, you could try using a heat gun on the wifi chip.

Cover everything you don't want to get too hot with foil and spray hot air over the chip. This would allow you to control time and temperature a lot more effectively.

I say this because this is the method I usually use to fix PS3's, XBOX's, PC components (GPU, MB, etc.), where the solder has developed microfisures or the chip has become badly seated.

Might have to give this one a punt. Shouldn't do any harm to other components if they're covered properly. And as the chip isn't working at the moment, can't do any MORE harm to it. Wish Apple would at least acknowledge this problem instead of doing what they've always been good at, which is talking, without saying anything.

Just to expand on my previous comment...

Having re-read the oven bake method I noticed he did mention a heat gun as probably being better.

As I own one, this is what I'll be using (with foil over the rest as stated in my last post). But if you don't own one, they're not really expensive... Expensive in the sense that you're contemplating putting your £100 PCB in your oven.

Can pick one up for £19.99 from Argos, which is the one I use, and is perfectly capable of any application you'll ever use it for.

The problem IMO of putting it in the oven, is if the solder totally melts, and your board isn't totally flat, the solder will run, which will cause shorts all over the place. Which, unless you're skilled at micro-electronics, will ruin your board. A heat gun can be moved away as soon as you see it melting, so is a lot safer (again IMO).

Another good reason for a heat gun is that electronic components, when heated up excessively will release toxins in the form of gasses which can prove harmful to you... Which floating around where you cook your dinner isn't always an amazing idea. Don't get me wrong, it's pretty **** unlikely (they have to get pretty **** hot), but still the risk is there.

I don't know that I'm convinced on the whole reflow thing. I'm not saying it doesn't work as it seem to be proven, it's just I can't get my head around the timing with the iOS 4 upgrade in killing my WIFI. And why is it the freezer trick works? Is it contracting the solder to seal the micro cracks or is it tricking a temp sensor? I still feels like a sensor issue to me. Could the baking do something to a temp sensor? I guess I'm still holding out some hope that an os update could fix it if it were software causing a high read on a sensor. Eh, what do I know. I don't even know if there is a sensor that would shut off WIFI if it thought it was too hot.

Your problem may be software related. Or even a toasted wifi chip. You just need to diagnose it as a problem with your solder joints or not. If your wifi failed due to fissured solder joints then the "Oven Trick" will fix it (done right of course). But if your wifi problem is due to anything other than fissured solder joints the oven trick won't do anything for you. However, be careful of the freezer trick. Some guys take their hot phone and put it straight into the freezer. Rapid cooling augments the fissures.

Bottom line: diagnosis.

The issue seems to be that as solder gets hot, and cools, and gets hot, and cools, over and over. It forms tiny cracks in the circuitry, and the seating of the chip. These cracks result in increased resitance on the circuit, as it's trying to bridge tiny gaps through tiny electronic shocks/sparks. Because of the increased resistance there's an increase in heat output.

Problem with Pb-free solder (that's lead btw), is it is well known in the electronics community to have these micro-fissures (they're the little cracks) occur... However, it's cheaper than lead based alternatives, so the industry has pretty much adopted it.

If you cool down the entire circuit (i.e. putting it in the freezer), there's obviously less heat. Electricity flows better at lower temperatures, and therefore the resistance is lowered, albeit temporarily.

By putting it in an oven (which is where ALL YOUR IPHONES have been at LEAST once in their lives) you can 'reflow' the solder joints, and re-seat the chip in the PCB.

The reason there are timing issues with an update is because during a firmware update, Apple (IMO anyway) tries to do far too much all at once. By this I mean, instead of releasing smaller more frequent updates, they release big updates that stress your used and pretty worn PCB for about 15 minutes of constant current. Which in turn creates a lot of heat, which again are part of the cracking.

It's a little like water in a crack in rocks, it freezes, which expands a little, then warms, where it returns to water and condenses. Over time this creates a bigger and bigger gap.

I've tried to explain this as best as I can. If you don't want to give it a go (don't really have much to lose if you have a heat gun and are careful, just don't melt anything), then you don't have to. But if you're in the same boat as most of us, where it tries to search for half a second, then seemingly timeouts, no software fix can ever resurrect it.

The choice is yours really.

Did you already try the heat gun?
Could it be possible to create some kind of (picture) tutorial? I think it would help a lot of people... I've got no idea how to start, but I would like to repair my wifi.
thx

I don't mind making a video of it... I'll need to find an able assistant though, so will probably have to wait until the weekend.

Watch this space.

Just thought I'd mention, this post now has over HALF A MILLION views... And Apple still think this is a minor problem that affects a very small number of their devices. ** them!

Message was edited by: MasterTeeee

mitjak, here's another

KoobcamUser fixed his with the Oven Trick http://discussions.apple.com/message.jspa?messageID=12071293#12071293

Cool, I uploaded a video on how I did the Oven Trick to fix wifi on YouTube this morning.

http://www.youtube.com/watch?v=l1azZWWkmSg

If you do a video on the heat gun method I'd like to link to your video. Please let me know. Thanks

(I agree, it's far from a minor problem, LOL. If it really is a widespread material defect it should be recalled.)

@ SimpleServe: good explanation and good video!
resoldering sounds to be a reasonable solution to non-software-related wifi problems. imo the "freezer short time solution" underpins this.

nevertheless i have some questions:
- how did you choose the parameters (temp. and time)? afaik the soldering temperatures of leadfree solder is somewhat higher.
- when manufacturing pcb's sometimes temperatur sensitive components are placed on the board after (reflow) soldering. are there such components on this pcb (which could be damaged by this resoldering procedure)?
- how many useres successfully repaired their phone by this method already?

thanks and regards

Hi paraglider,

I chose 385F and 7 minutes because that was around the lower end of what was being used successfully here http://hardforum.com/showthread.php?t=1421792

Some used longer times and higher temps. Also, I knew I wouldn't be able to match the reflow temperature and time profiles I was finding shown for lead-free solder production. I saw some that tried to match the profiles by adjusting heat in their ovens but I decided to go for a more simple and repeatable approach.

I do not know if Apple places any components on after the reflow. However, the stickers on my EMI shield did not appear affected after baking. Maybe they, along with the shield and everything underneath are designed to go through the oven.

To my knowledge, there are 5 successes and 3 failures. 2 of the 3 failures were disasters causing PCB failure. 1 of the 3 failures didn't fix the wifi but the PCB worked just as it had before. One of the 2 PCB failures may or may not have been due to moving the PCB immediately after baking the board. He said as soon as the 7 minutes was up he removed the baking sheet and PCB to let it cool on his desk. IDK if immediate movement played a part in the failure or not. The person who had the other PCB failure said he followed the complete instructions except that he didn't use a thermometer. However, unless his oven temp was way off I don't know if that had an effect because of the reports of those who baked boards (at HardForums) at temps as high as 400F.

So that's what I know to date. As I get more feedback I will annotate the video on YouTube and add information to the video text.