We have a Polycom Soundstation that will not go on-hook. I have troubleshot to the power-supply (had access to a good unit). Once power supply is energized and RJ11 is plugged in POTS line goes off-hook and will not go back on-hook. At first I thought it was a cabling issue (resistance short across the par) However replacing RJ11 plug did nothing. Must be internal?

Anyone know the details of these. I had assumed that it was a passive device (transformer and pass thru of POTS) but more seems to be going on.

Worth cracking open? Anything repairable inside?