comdial executech 854 ksu power outage

[nutek00]

After the power outage all stations make humming crackling noise, cant make or receive calls. Disconnected all the lines coming from the outside and the still the same. Please help

 

[mforrence]

You sure that's an 854, and not 824? If so, it's a flat-pack with no end-user replaceable parts. Disconnect all but one phone and see what happens - if that phone comes up, it may be one station bringing it down. If still no joy, your KSU is likely toast. It may have lost the memory retention battery or similar fate. It's circa early 1990s system - so 20+/- years old and has long been out of production. You can likely find used KSU from refurb source. They program via telephone, and manual should be readily available. Good luck on quick resolution.