solder cracked on pcb potterton profile 60e?

Intermittent clicking noise and occasional sparking. Having seen the solder joints clearly with a magnifying glass the cracks were obvious on the sparking connector. Turned power off and resoldered then checked with circuit tester to ensure joints were sound.
When I reconnected all leads and powered on, only the pump could be heard at switch on. Tried the reset button just in case, but still no action.

Any ideas?

Paul
April 2008