Electronic Alarms and Home Security Devices - LCD 600 KEy pad

I have a LCD 600 Key Pad , with a Pc 2550 control panel.
I just bought this home and i am trying to see if this system works.
I bought a new battery and the system came alive. found a couple window sensors bad.
repaired all sensors but my batter went dead over night. now after charging battery, my lcd 600 key pads will not come on, but my pc2550 control board LED will bink. I tested all fuses and they are good.
Is my control panel dead?
I have a transformer plugged in for the A/c power
Any help would be appreicated.
Thanks

The fact that your battery died overnight tells me that you probably have a dead or dying transformer. These older systems will _try_ to start up on battery power, but cannot operate on it for more than a few hours. Check the output of the transformer.

My transformer is working fine. I tested the voltage and it is within specs. Just be connecting the battery it would light up the keypads, I do hear clicks when battery is connected but still no power to keypads.

Assuming that you have tested the three fuses on the main board, check the output at the battery and aux power terminals. If you aren't seeing 12.5-13.5VDC, but you have 16.5 VAC at the AC power terminals, then the only conclusion left is a failed motherboard.