5s Loudspeaker stopped, possible short?...
A few days ago the loudspeaker in my iPhone 5s suddenly stopped working. No water damage, no drops, no distortion prior, nothing... it was working one minute then literally the next it wasn't.
I've reset settings, checked that it's not stuck in headphones mode, updated to iOS11 and the headphones work fine.
I had changed the battery 1 week prior but the loudspeaker had no obvious issues afterwards, and seemed to function correctly.
So I bought a replacement loudspeaker and installed it, but no dice.
When I tested the speaker contacts with a multi-meter, I could see slight milli-voltage change when I raised or lowered the volume of a song playing, so I connected some wires to the old loudspeaker and hooked it up to a headphone jack to test that it was functioning (it was).
I then cleaned the two contacts in the phone and held the wires directly on each contact, no sound... however when I accidentally touched the wire on the metal on the case to the side of the contacts, I noticed sound...
So upon further testing I figured out that if I hold one of the wires (that's connected to the old loudspeaker) on to the left hand contact in the phone, and the other wire on any other metal surface in the phone; sim-card holder, metal frame, metal plate covering screen connectors, etc., the speaker works!
So it seems that there is a short(?) of some sort somewhere, causing the speaker to not work when connected to the actual contacts... but does allow it to work when one side of the speaker is connected to the left hand contact on the phone, and the other side of the speaker is touched/connected to seemingly any metal in the phone... (Let me know if this is not a clear enough description and I'll clarify further).
I have no idea which part(s) to test or replace now (or even if I can do so without micro-soldering?).
Does anyone have any idea of what it could be, or at least what to test next?
I appreciate any advice.
EDIT: Made a new ground. Speaker works but distorted.
Is this a good question?