We've had this problem with a fire alarm monitoring system at a facility I managed,, We'd get this "trouble alarm", basically means something is wrong within the system, not a fire,,, anyway we'v has three alarm tech companies try and fine the problem , even paid thousands to replace the motherboard,, the problem still persisted, Only solution will be bite the bullet, spend a fortune to scrap everything and build a new system.

Point??
All it take is the right amount of money to fix a problem right.