Wifi signal very low after repair

1. Tap Settings

2. Tap General

3. Tap Reset

4. Tap Reset Network Settings

This will cause your iPhone to restart, and will delete any stored Wi-Fi passwords as well as DNS settings and more. It may, however, restore your ability to join a stubborn wireless network. I also attach this interesting link just in case....its about the repair of the WIFI and reflowing the logic board.http://www.iphonetiquicia.com/iphone-wif... let us know what works for you and how it is progressing....good luck

Did not work for me, Signals appear to be very weak

you can get the 3G antenna signal coil on the back of the logicboard here

Bumping an old post, but in my experience a weak wifi signal (as opposed to no wifi) is often caused by damaged cable for connector 6. If you did another repair then you may have stressed the cable a bit and broken a connection. Here are the instructions for this repair-

Remplacement de l'antenne GPS de l'iPhone 3G

The iFixit Guide refers to this as the GPS atenna module, but pretty sure it is for both GPS and wifi.

Its one of the more involved iPhone repairs because you have to first remove the large cable assembly that controls the volume, power, etc. Getting that back on is sort of a pain, but just be patient and you should be fine. Just look at the pictures for reference of the original arrangement.

IFixit doesn't seem to sell this part anymore (or else I would post that link), but it is available on EBay for pretty cheap. Well worth the benefit of good wifi again. Another possibility is that you damaged the connector on the motherboard itself, but that is generally less likely unless you really applied too much force.