Call to the above electric hob, compliant both left rings cut out sometimes.
Test hob but as usual worked perfectly. Open appliance up and check for loose connection in mains block and control PCB.
Unable to find a problem so refit and test again all still OK.
Called back 3 days later still has an intermittent fault. Returned, but still unable to find a problem.
Apparently it sometimes cuts out when in use or fails to heat up from cold so it’s not ‘heat’ related. When the rings fail to work the display still shows correctly.
Any suggestions what this could be causing the intermittent fault?