Ooooo, its SOOO annoying isn't it!
Take the clocks out and check the PCB (Printed Circuit Board on the back). If there's a dodgy connection there then it can stop things working. That's what happened with mine (found it out after checking connections, relays, everything. Very frustrating :roll: ).
My answer was to solder the connection as a temporary measure whilst I bought some new clocks so I new it would be properly sorted.
If that is the problem then you can probably get a new PCB, but I'd say it'd be cheaper just to buy the clocks and everything from someone on here.