I think you have the most compelling debug result so far: If the ringing occurs even in "Airplane" mode, then that suggests it is *not* related to low signal strength (which was an inverse proxy for Power Amplifier level, thus battery current pulses coupling to speaker). If more folks would confirm this I think that would be helpful -- ruling out the radio can help focus on other issues. We don't want to be barking up the wrong tree.
What I suggest to try next is: While it's ringing, start shutting down serivces one by one to see if one of them is correlated to the ringing (when you re-start the phone these services will automatically start up again).
Settings --> Apps --> Running
Now choose one and hit "stop". Keep going until (hopefully) the ringing stops.
If the ringing still doesn't stop after shutting down every possible process/service then I think it's a bad power supply design. Otherwise, if you can trace it to a particular app process/service then maybe they can find a software solution.
For a root cause, we're hopefully looking for some type of process or service which periodically causes the phone to draw a lot of current from the power supply which is magnetically coupling to the speaker. For example, anything which requires a big memory access is going to use a lot of processor and memory interface I/O may do it. On the other hand it may be unrelated to any process/service and simply it could be that in standby mode where there is only small standby leakage currents to the apps processor and memory that the switching power supply is operating in an extreme discontinous mode (which is a high efficiency low battery current technique), with very low average current but short high peak currents (which are more likely to magnetically couple to the speaker). This is kind of supported by the reported behavior that when one starts a phone call, the ringing stops (it could be greatly increasing the average current and moving the supply operating region out of this extreme discontinuous mode).
In my post above I mentioned I closed all but one or two running applications when it was "ringing" and nothing changed. I believe the only application running was the HTC Sense Input process/service which didn't have the close option.
I put my old Sims card I had in the phone back into the phone and went to
the spot where I had issue and low and behold it started doing it again.
Started faintly ringing and I was getting poor service. I made a call and
it stopped. Turned the phone off took old Sims out and replaced with new
Sims card. Powered back on and got good connection, almost full bars 4G
stayed in the area for about 20 minutes to see if anything was going to
happen nothing. Took the Sims out and replaced with old Sims and about 5
minutes later poor coverage and ringing began. Made call to stop. Repeated
the second step and issue stopped. Maybe there are some bad Sims going
around not sure but mine seems to be fine with new Sims can't say for sure
but it seems like it could be the issue.
I have been working with HTC on this issue - i called them and opened a ticket and I suggest that all of the people who are experiencing the same issue do the same, for a couple of reasons:
1. It documents to Verizon that you have been experiencing an issue and the date at which you reported the issue.
2. It documents to HTC all of the issues that you have been experiencing - the more there are, the more likely action will be taken in a decent amount of time.
I want to share with you the last correspondence that I have with them:
I am sorry to hear that turning off fast boot did not resolve this. I would like to try running the phone in safe mode which disables all third party apps as they could cause this. You can put the phone in safe mode by either press and holding on the power key until a phone options menu comes up (should take about 5 seconds) and then press and hold on the restart option until an option to restart to safe mode pops up(should take about 3 seconds), or by turning off fast boot, power he phone off, turn the phone back on and hold the volume down button once you see the HTC logo, you need to continue pressing the volume down key until you reach your home screen where the words "safe mode" will be displayed in the bottom left corner of your screen. I also would like you to obtain a new sim card from Verizon and have them reprovision your network account. You should be able to have both of the done in a corporate Verizon store. Please reply to this email to let me know how your phone is working after these steps are taken.
This is prior correspondence:
Thank you for replying. I'm seeing, in the link that you provided that a number of people in that forum had this issue, even on different phones but on Verizon. I'd like to know if you've tried turning off fastboot and then seeing if your phone still makes the noise? To turn off fastboot go to Settings>Power>and uncheck fastboot. Then power the phone off/on and use it normally. Let us know if this has any affect on the noise that you've heard from the phone.
I have not had the constant ringing issue as of late, i have had my phone in very fringe areas of coverage even down to one bar.
I will update once i have more information to share.
Excellent incident management approach on your part along with apparent favorable resolution. I'm convinced enough to (finally) go pick up this phone. I hope others on the thread along with the OP will try this solution and report back.
Just wanted to chime in that I've had it happen twice on my HTC One... And I've had fast boot turned off since day one (I got mine on release day), so I really don't think it has to deal with that. And yeah, I got the sound to go away by rebooting the phone (again, that worked because I had fastboot off). As for the when it happened, I can't remember what I was doing when it happened the first time, but the 2nd time I was driving around the Twin Cities with my friend (I believe from the Mall of America to Minneapolis), so I don't know what to think.
Not sure if it's worth noting, but I did get a new Micro SIM when I bought this phone (they wouldn't let me use my old Micro SIM from my Galaxy Nexus because that one didn't have NFC built into it). Any suggestions on what I should try, outside of just getting a new SIM?
The problem analyzing the ringing, is that once it starts ringing nothing can stop it but making or receiving a call. The ringing would always start for me within 20 minutes of me sitting at my work desk in the morning (low-signal at work). If I didn't make a call or receive a call it would still be ringing when I get home. When I wanted to show Verizon the problem, I would sit at my desk (ringing would start), then I would turn my phone off.... after work I would drive to verizon and turn the phone on... it would still be ringing for them). But over a weekend where I don't go to work... It would never START ringing. It would ring all weekend if I never made a call from the last work day... but the ringing only STARTS when I'm at the low signal area at my work desk. Airplane mode, shutting down apps, etc never mattered once the ringing starts... its more about what causes it to start.
The ringing got so bad for me on my second phone that even when the phone was completely off (the ringing started...so I turned the phone off), it would still ring periodically on its own WHEN THE PHONE WAS OFF! If the phone had been ringing and I turned it off, I could make it ring by tapping the power button (not hold it down long enough to turn the phone on).
On my second phone, I made the exchange at 8pm and at 8am the next morning I sat at my desk and the ringing imediately started. I never downloaded an app, changed a setting, or even sent a text message.
I switched to HTC One on AT&T and things are working perfect for almost a week now. That is the only solution I could come up with.
Between all the various posts on this thread and on the baord, this phone sounds like a piece of junk. gaps in the frame, radio issues, faint humming.
I would lean towards the droid Maxx or droid X or Gs4 over this thing.