Hello,
I have purchased Tenma 2064549 ( https://uk.farnell.com/tenma/21-10115-uk/soldering-station-60w-220v-uk/dp/2064549 ) 3 years ago and it properly worked until heater element get damaged few days ago.
I replaced the element with exact replacement part that recommended by manufacture. ( https://uk.farnell.com/tenma/cbb018722/heating-element-60w-at938d-at60d/dp/2113923?ost=2113923 )
Now it heating properly. But, Temperature on the display is incorrect. What happen is when turn on the soldering station it shows about 50C. When gradually heating up that display value is decreasing to 0C.
This phenomenon happen when reverse the thermocouple polarity. But, This soldering station has only one wire that connected to special spring like sensing element to get the temperature sensing. I think it masseurs the voltage difference between common ground.
I have checked polarity of heating element and its correct. I also reverse the heating element polarity and get same result.
Hope my description is clear for you and your hope solutions/ideas.
Thank in advanced.