Time Capsule 2TB wireless Intermittent issues

Once a week the wireless stops working. I disconnect the power cord to time capsure for 30 seconds to 1 minutes and then it works normal for a 3 to 4 days and again the same problem. This is happening from past one month. Anyone experiencing this issue? Please help.

I connect using: DHCP

Router Mode: DHCP and NAT

I have Motorola Modem only which is working perfectly fine from past 9-10 months. While troubleshooting I have isolated the problem in Time Capsule , the modem is working fine.

I have updated the firmware last week and the current versions are:

Airport Utility: Version: 6.3.1 (631.4)

Time Capsule: Version: 7.6.4