Fourth generation iPhone. Repair is straightforward, but the front glass and LCD must be replaced as a unit. GSM / 8, 16, or 32 GB capacity / Model A1332 / Black and White.

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Replacing front panel. Pressure contact came off of logic board.

Replacing the front lcd/digitizer and glass with a unit I bought from ifixit.com due to a fall and major glass break.

Picture of broken glass

Teardown went fine. The front install went fine. (love those side screws and washers).

When I went to put in the logic board, I found that a contact piece had come off the very top of the logic board. This piece makes contact with the outer frame.

Here is a stock photo of the logic board showing where this contact goes

Here are front and back pictures of the clip/contact piece and our logic board:

Front

Back

I'm very nearly certain that this has to be reattached. I'm also pretty certain that it needs to be soldered so that it is conductive to the logic board.

I am not at all experienced soldering, so I'm wary of trying this. Anyone have any experience with liquid solder or conductive adhesives?

At this point, the phone is useless as it was when it fell in the parking lot - so soldering on the logic board might have to be something I attempt.

So my questions are:

1. Anyone know of a liquid solder or glue that will work well?

2. Anyone have a good source for a replacement logic board? (we've already got the cost of the screen invested, so we may have to spend further)

3. Anyone know exactly what this piece does and maybe I don't need to do anything?

Thanks in advance to anyone who can offer some advice. I appreciate your time.

Answered! View the answer I have this problem too

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I'm cautiously optimistic that I fixed it. I used a product from MG Chemicals (a Canadian company) called Silver Conductive Epoxy. It was not cheap as Jeff Stephens suggests. It was $34.99 for .35 oz (14 g).

I glued the clip back onto the motherboard. After the curing time of 4 hours, I reassembled the phone. At this stage, it all works. My partner is syncing his stuff back onto it. The screen and digitizer work. Wifi and phone both work. Haven't tested Bluetooth yet. Both cameras are working also. It's charging and moving music and apps over as I type.

I'm not certain that the epoxy will hold forever, if and when it fails, I'll learn to solder or just re-glue it if our next phone upgrade is in the near future.

Thanks for the help from the support folks at ifixit.com and also the answers here. I appreciate it.

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Well, that's excellent news, tomkarl. Here's to what looks like a successful fix.

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Unfortunately there is no easy answer. The loose clip or EMI finger, as you mentioned, is intended to make a conductive contact between the logic board and the metal outer frame. I can't say for certain how critical this contact is, but I expect it is intended to reduce interference with the phone's radio signals. You might get away with a functioning phone with out the tab, but it may experience more connection troubles.

Assembly and disassembly of the iPhone 4 is a bear (as you know by now) so a reassembly just to try it out without the little tab may not make sense.

It is hard to tell from your photo of the back of the logic board what has been left behind where the EMI finger tore off. If the circuit trace is still there you may be able to resolder the component with a very fine tip iron. If the circuit trace was peeled off with the EMI finger the repair will be more tricky and require that you find some way to expose a fresh bit of the circuit trace.

Electric conductive adhesive could work but the good stuff can be difficult to find retail, it isn't cheap, and often isn't in tiny quantities. Master Bond produces all sorts of adhesives with a variety of properties. To find it or similar products you will have to find an electronics shop that is more savvy than Radio Shack, and with luck such a shop might be able to help you chose an appropriate adhesive. I would avoid the cheapie stuff like wire glue and other things sold as liquid solder. Most of these will make a weak mechanical bond and some introduce too much resistance.

Unfortunately finding a replacement iPhone 4 logic board will be difficult or expensive. With all these road blocks, trying it out without the EMI finger looks more attractive.

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tomkarl will be eternally grateful.
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