This manual is very helpfull to use the Power Supply. All technical information has been available.
For service use the circuit diagrams are very good.
Text excerpt from page 13 (click to view)
Before you use the ovens you should wipe them out with a damp cloth to remove any dust.
Main oven - There are zones of heat within
the oven. The temperature in the middle is the gas mark you have chosen. The top of the oven is slightly hotter and the lower shelf slightly cooler. The base of the oven is quite a lot cooler. You can make use of these heat zones when you are cooking foods that need different temperatures all at the same time. If you are cooking more than one tray of similar items, for example cakes or biscuits, swap the trays around during cooking. Or you can remove the top tray when the food is cooked and move the lower tray to the higher shelf to finish cooking. Second oven - You should turn food round during the cooking time.
You can slot the oven shelves into any of five positions in the main oven and any of the two positions in the second oven. Positions are counted from the top downwards. The shelf in the grill/second oven is different from the shelves in the main oven. Only use the shelf with the solid metal plate underneath it in the grill/second oven. The plate may glow red when you are using the oven. This will not affect the cooking performance. 13