Check your repair.
If wiring to bell box is wrong, it will sound off. No other reason, except mentioned above, i.e tamper switch not operated, is cover fully seated, and tight?? Did you catch the lever for the tamper micro switch, If it is a micro switch. is tamper indicated on control? If not, would think your repair. Check it, very easy to connect wrong. done it myself.
SD, June 2011