Re: cannon chester ignition problem
If no spark can be seen at an electrode tip on only a few electrodes, (not all) then, its probably shorting out somewhere on that individual ignition circuit
most likely components
cracked electrode
or a weakness in the electrode leads
doubtful, but also possible, is the ignition generator itself
Some electrodes come complete with a lead, some come seperate)
This is a job for a corgi registered engineer
Prior to ringing an engineer, check carefully around the hotplate electrodes that arent sparking for signs of cracking etc
safety first, power off etc