Ad: " RARE! ALMOST IMPOSSIBLE TO FIND! THE COOLEST RETRO OVEN EVER! Black CALORIC gas wall oven. Works beautifully - was used daily for the past 13 years. Selling it due to a recent kitchen remodel. Clock needs to be replaced - (available through online appliance parts vendors). "
Very cool oven. But "easily replaceable" is definitely one of my major seller pet peeves. Some people will say anything can be replaced without having a clue about it.
The clock looks suspiciously like a Telechron. If so, and if it's not too difficult to get to, either replacing or rejuvenating the rotor (rotors are frequently listed on eBay) may be all that it needs to get it running again.