Kuppersbusch oven clock

[DIYspanner]

Do the clocks on these older ovens have battery backup to prevent loss of time when the wall isolator is switched off?

I've set it once and switched off at the wall for 10 mins and the time was still set whereas if off for a few hours, the time defaults.

 

[Murdochcat]

What do the MIs say?

 

[Jurassicspark]

For a short period of time, yes the oven will retain the time but if you leave it unplugged for a long time it will forget due to the capacitors discharging.

A simple crystal oscillator with a 555ic can easily achieve this.