My mini-frig uses one 12704 40 mm x 40 mm Peltier. Can a 12705 or 12706 size be used to replace it? I do not want to buy five 12704's.

Question

My mini-frig uses one 12704 40 mm x 40 mm Peltier.  Can a 12705 or 12706 size be used to replace it?  I do not want to buy five 12704's.

Accepted Answer

Most likely not the Peltier, having fixed a couple of (mini coolers, wine cellars and other thermal devices), the problem happens from Electrolytic capacitors that fail with age or are substandard.
To check if the Peltier is bad, remove it from the circuit board (it may be connected to a heat sink with thermal paste and screws) test it out of circuit using AA battery.  When you connect the battery make sure you use the correct polarity, one side of the Peltier will be cold and reverse side will be hot which means its good, you don't have to reach reverse side full hot temperature.
So if it's good, the next step if you don't have a schematic take a closeup picture of the circuit board, or better take notes. Write down the Electrolytic capacitors (position on the circuit board, capacitor values, polarity, physical size, swollen, leaking). 
Best way to check the capacitors is to unsolder them from the board and use a capacitor checker to check their values (voltage, ESD, Ohms) you will get accurate readings without any other components on the circuit board returning misleading values. 
I replaced all the Electrolytic capacitors on everything I repaired, and all devices work like brand new, going on four years with no failures. 
If you opt to replace all the Electrolytic capacitors, buy quality (Nichicon, Panasonic, Leylon) to name a few. Hope this information helps.

TEC1-12704 Thermoelectric Cooler Peltier of Semiconductor Refrigeration, 5PCS TEC1-12704 (40*40), 40mm x 40mm x 3.6mm, Desktop Compatible

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