Following up on my repair effort, I'll document what I found in case anyone going down this road stumbles on this writeup.

In short the unit uses a Peltier module heat pump to both heat and cool the yogurt container. The Peltier module was bad in my unit - gave a constant ~30K ohms reading, connected it to a 12vdc battery source, no heat what so ever.
The module is a TEC1-12705.
To my surprise none of the usual electron parts houses have them (Mouser, Digikey, avnet, allied, newark, etc.) Amazon has them ranging in price from $6 to $10 from varying sources and from what I see in the reviews, all parts are of questionable quality. To my surprise, they are available through Walmart!
Not sure where to get the OEM part - suggestions? pointers appreciated.

Description of the unit, it contains:
1) 5 VDC 6A smps, which feeds a...
2) a 2"x3" micro based control module that contains connections for: the Peltier module, a rtd/thermister temp sensor, power supply input.
3) the heat/cool stack composed of 1.25" aluminum heat block encased in styrofoam, the peltier module, a massive Al finned heatsink (5"x 2.5") and a 3" fan bolted to the finned heatsink.

Getting the unit apart is a little tricky because it has 4 plastic fingers that lock the bottom half of the unit to the top half - need to simultaneously unlock all four tabs then separate the top and bottom.

Couldn't see any obvious design or implementation screwups, although I question why there is a 1.25" thick piece of aluminum between the Peltier module and the bottom of the yogurt container. I'll need to do some heat transfer calcs to see if they are controlling the module correctly and take some temp measurements to infer their desired (required) heating and cooling temps.

From what I could tell on the scope the output to the Peltier module was fairly smooth DC voltage that is (my guess) a LPF PWM output to a power transistor (MOSFET?) from the microcontroller The markings on the chip were unreadable due to some clear coat that was put on the chip. A lot of speculation here since I could not read a lot of the component markings. My googlefu failed to turn up anything about the components, although the PS looks like it is an off the shelf module from somewhere.


Next step is to get the replacement Peltier module, perhaps upgrade the thermal silicon grease, and reassemble.
J