Why isn't my Android 4 getting a signal but keeps turning itself on and off saying no service found?

[AC Question]

my android 4 isnt getting a signal but it keeps turning itself on and of saying no service found

took to phone shop he said the battery was low but the battery now is 90% made a phone call this morning went to use it again now its aint got a single and keeps shutting on and off scan it with 360 security says no virus or malware found please help I use phone for business

 

[B. Diddy]

Re: my android 4 isnt getting a signal but it keeps turning itself on and of saying no service found

Welcome to Android Central! Which phone? It could be a faulty battery, a faulty Power switch, or something more serious like the motherboard. The signal issues make me lean towards a motherboard issue.