Sunpentown wine cooler wc-20TL. The thermostat temp stays at76deg, even when set t 55deg. It doesn't cool inside. Any solution?

If after adjusting your thermostat to desired temp and is still cooling. The thermostat is bad or your relay is bad
If you disconnect the thermostat and the compressor stops it most likely a bad thermostat
If you disconnect the relay from
The thermostat and it stay running it is the relay. It is sticking
If possible store you wine somewhere else and shut the unit down and unplug for 10 to 20 minutes this may cause some melt of condensation some water may be on the floor if is to cold
This may also reset the system.

Here is a link to the manual. I hope it helps, because it says nothing about putting on handle. Maybe pics will help.
http://site.sunpentown.com/wc-30U_manual.pdf

Hello,
You should refer to the user manual to help you troubleshoot your equipment located Here: http://www.manualslib.com/manual/574948/Sunpentown-Wc-30u.html
I hope this helps!
Good Luck!
Rich Lilja

Defective compressor. Refrigerant leak. Defective thermostat. If the compressor is running, then it has a refrigerant leak.

Usually with thermoelectrics they either work or they dont. Not easily repairable unless you are a competent technician as the components need metering. Sounds like a heater element gone.

Our magic chef wine cooler (mcwc50dbt) when temp is set on digital panel at 45-50 it jumps immediately back to 70 degrees constantly

Small refrigeration units like this one like to fail to cool by developing a small leak and slowly
leaking refrigerant.
THERMOSTAT FAILURE CHECK:
A technician will check the thermostat using using a DMM (digital multimeter). But you can suspect the thermostat if you set the thermostat high and the compressor motor does not run,
then set thermostat low, and the compressor motor also doesn't run - in other words, the thermostat is failing to start the refrigerator's refrigeration system no matter what its setting - an obvious failure of the thermostat.
COMPRESSOR FAILURE CHECK:
If the compressor is dying, you would hear the compressor running almost constantly, but not
sounding quite right (uneven noise, clunking, tapping).
REFRIGERANT LEAK CHECK:
If you unit is low on refrigerant (due to a leak), the compressor motor will be running
almost constantly, but it will sound Ok.

There is a thermostat that is seen on the unit , you will have to set the thermostat to a lower level. Also check if there is any gasket leak to confirm that the cooling does not stay.
Keep the cooler away from hot spots to encourage the cooling to stay.

Check your thermostat setting, if the setting is ok then something wrong with your thermostat control.

Few things to check here. If the compressor is not running then the problem may be a bad thermostat or the compressor start device (ptc starter). Most common would be the thermostat on wine coolers. Also need to check if the fan is running. If everything is running then you have a sealed system problem. If the fan is the only thing that is not running that will cause a no cool situation.