My Teka HA830 oven, installed in 2008.
It developed a fault about 1 month ago.
The timer setting buttons. (the "down" button stopped working).
After a bit of probing I proved the button assembly was to blame.
I searched the internet and found the exact module in Spares2repair.
I ordered a replacement - this arrived in about 10 days
Removing the old unit requires:
1. removing 2 screws holding the oven in place
2. removing 2 screws and removing the shield over the front panel display (inside the oven)
3. disconnecting a 3 wire plug
4. from the glass front panel