Loud static when using Cortelco T-903B

[Weepingangel]

A year or two ago, I acquired a Cortelco corded T-903B (Centurion Extended Basic 3691 is the closest match on the Cortelco legacy phones web page) phone via Amazon, and recently I decided to hook it up to my Ooma Telo router and use it. I discovered that on going off hook I get loud static that drowns out the dial tone. I then made a test call to the Harvard Sentences number, and the audio there was overwhelmed with static. I bypassed the phone wiring on my desk, and connected the 3691 directly to the Ooma Telo, and still got the loud static drowning out the dial tone. Is there an easy solution to this, (like perhaps eliminating a ground loop or turning off the status indicator) or do I have to acquire the legacy PBX that this phone would normally be connected to?

[murphy]

The Telo needs a standard analog phone. It sounds like your T903B is not an analog phone.

[Weepingangel]

Update: through comparison by swapping handsets around, I was able to get a clear dial tone. I put a different handset on the Cortelco phone, and got a clear dial tone, and also got a clear dial tone when I connected the handset from the Cortelco on a different phone. I then connected the original handset to the Cortelco, opened it up, and carefully wiggled some of the capacitors. I found one that, when wiggled, made the distortion and static cut in and out. That said, either one of the solder joints under this cap is imperfect, or the cap itself is borked and requires replacement. Shortly here after dinner I'll touch up solder joints on the underside of the phone's main board that look sketchy, and see if that helps. If not, then that narrows the problem down to one or more borked caps.

I got some helpful information and advice from a user in the Exploding The Phone Facebook group, which is what led me to examining the main board.