Ademco 50P - Unable To Disarm

["Don" <dedeaux@xxxxxxxxxxx>]

Hello to All,

I am suddenly unable to disarm my Ademco 50P system.  Any and all help
appreciated.

Details:

- system was working fine for months.

- worker with key entered building unaware the alarm had been
activated.  When the alarm went off, he pushed the OFF (#1) button on
the keypad.  There are seven active model 6150 keypads installed.

- awakened by alarm, I entered my code then the OFF button on a
different keypad.  I do not know whether the worker and I were punching
buttons at the same time.

- the alarm continued rather than going into DISARMED.  After several
attempts to disarm, I successfull experimented in changing the armed
state from AWAY to STAY and back again.  Again I do not know whether
the worker was still pressing the OFF key.

- I answered Central Station's question that all humans were okay, I
had  them put my system into test.

- I then turned the system off for varying periods of time by throwing
the ac current switch and pulling battery connections.  I hoped this
would somehow reset the system.  That was yesterday.

- After leaving the system unpowered overnight, I just (09:30 EST)
turned it on... then off.  The system continues to stay armed.

Any thoughts?

TIA

Don Davis