OK, I've read the thread.
Possible causes suggested here:
- Heat causes mic circuit to fail
- Slider causes wear and damage to a mic connection
- The old tricky headphone socket
- The Touchvol app
- The SPL meter app
- Some random/unidentified patch or app
- Uberkernel - default setting
- Some interaction between 2.2.4 and specifically Pre3 H/W
My situation is noted above. It has only started happening recently and is always solved by reboot so far.
- This phone has never been doctored by me. I'm pretty sure it was BNIB when purchased. I can't remember if there was an OS update or if it came with the 2.2.4 it is running.
- It has been dropped a few times, short distances to carpet I think - no noticable damage beyond the normal wear.
- I have the usual patches but no major customisation.
- I do not have Touchvol or SPL meter installed
- I did install Uberkernel - probably in the last few months
- I have recently downloaded a lot of apps. I rearranged my launcher cards to organise this, but I think I previously added one new card where new apps appear.
- Right now, the phone is set to 2G only - I doubt this is the cause.
- UK / Euro unlocked
My untested theories:
- Hardware failure. I think it's S/W. If it's H/W, I'm out of luck.
- Uberkernel - could be, but the symptom took a while to show up.
- Patches - what patches would affect the microphone system? Unlikely.
- Leftfield theory: The Definitive Guide to Backing up and Restoring your webOS Device | webOS Nation
This may only relate to save/restore, but this app has moved 'relatively' by the creation and shuffling of the launcher cards. Probably irrelevant, but it is an audio app...
If you are running webOS 2.0 or higher, you need to ensure that the Voice Dial app is the last app on your first launcher page. The Launcher script in Save/Restore may not save any items on the first launcher page after the Voice Dial app due to an oddity of webOS 2.0
I just ran quick tests and got a modem error 20...? On a digital phone, I guess a modem is required for calling. Maybe it's my network setting. No problems with wifi.
In conclusion, I think I will move the voice dial app and run save/restore, then remove uberkernel. I will try Mutoidi's tests method to fix as it should be quicker than a reboot. Then there's posting patch lists and trying to eliminate them...
My feeling is that this is S/W. If a reboot is fixing it, that suggests that something is either progressively putting the mic in some kind of error state (e.g lowering the standard mic volume/sensitivity) or a random error is cutting the volume.
The problem is of course, testing with various configurations over time.