Haven Thermocouple Calibrator

[Mr Eastwood]

I bought one of these a few years back on Ebay and I was going to tear it down but didn't get around it;  I have since got hold of a Microcal Plus so, I thought I would tear the Haven and have a look inside.

Some things I noticed were;  80C39HC uC,  8K eprom chip ,  12 adc chip (icl 7109) which uses an external tc04bc634ak 1.25v bandgap ref @50ppm,  a few M82C53's doing I/O and interestingly a  MM57409N number cruncher chip! 

[Mr Eastwood]

Just to add, the t/c input posts were screwed to a fairly thick aluminium plate with a small hole in, which inside was inset with a AD590KH, this is to measure the cold junction temperature.