Tecnik range Cooke duel fuel

modelTKC 1285
S/n 3n0173d00621

Cou

Any idea ple of faults reported,

Main oven..no heat on eithe half or full setting no voltage when selected, although on conventional oven setting grill element works
Along with base element

2nd fault on smaller oven, was tripping rcd..fault to Earth on grill element..when setting for conventional oven. No voltage at base element.

Quick inspection of selector switch( without removing top) with torch appear ok
Not having wiring diagram any help welcome

Graham