No audio - Obi100

[Lemis]

I've been using Obi100 for 4+ years without problem, but now I'm here asking for a help.

Setup
Obi100
Sp1: Callcentric
Sp2: GV

Outgoing: GV
Incoming: GV forwarded to CC

The last it worked normally was 7/07. Then on 7/28 I noticed I didn't get a dial tone. Found out GV was backing off and quickly updated to build 2886. Now the real story begins here.  I still didn't get a dial tone. Went back to ObiTalk checking and testing.  I found out I could receive a call but couldn't hear at all. While testing, I found out if I use a speakerphone  I could hear a dial tone and incoming call.  After countless testing I concluded my old Panasonic phone (KX-TG2257) has had its day – Thank you, RIP.

Bought a replacement Panasonic KX-TGDA20, charged a new battery, made a few calls with success.
Following day it's back! No dial tone, but this time I could hear a faint audio thru handset's earpiece. On speakerphone, it works fine. Tweaked ChannelTxGain (as well as Rx)all the way up to 12.  Rebooted a few times via web.  It's still the same.

So it wasn't my phone? Can anybody help?  Thank you.

[drgeoff]

I don't know the internals of Panasonic phones so the following is a (only slightly more educated than completely random) guess.

The dc voltage generator circuit in the OBi100 has gone faulty, intermittently producing no or zero volts.  When you use a handset it needs those volts to operate, hence you hear nothing.  When you use a speakerphone, it has its own power supply and can still work with the audio signal that the OBi is putting out on its PHONE jack.

When not working properly, log in to the OBi's local interface, click on Status, then Phone Status.  Do you see similar values to those in the screenshot?

[Lemis]

Thank you drgeoff for your reply. It's a logical explanation.
I checked Phone Status, it showed VBAT 11.8 first, then when I changed outlet it showed 11.9.  Everything else is same as yours.  (Attachment is from a different outlet)

One thing puzzling me is the new phone worked briefly...   If the problem is with Obi power adaptor, I'll get a new 100. And before that I'll check with Obihai if they sell an adaptor only.

[drgeoff]

I was referring to the DC-DC converter(s) inside the OBi100, not the wall-wart.

[Lemis]

I paused and read the word 'DC' few times. Thanks for the clarification.

BTW, I did not know 100 is no longer sold except someone selling old stocks for over $100 or used at the price I paid for new.