I dismantled a non functional one to see if I could see anything wrong. 1980's electronics in all it's red tinged glory.

It is all painted with some sort of red varnish.

I had tried to reset etc but no joy and do not need to get this one repaired.

I do have some spare unit's but thought you might be interested to see what is in there.

At least the prawns look well-cooked.

CMOS technology... I see a few CD4011 NAND gates (known for dying when you look at them), a few op amps, a few X-NOR gates and what appear to be a couple of counters. I'd put money on one or more of the CMOS gates being dead.