Note or photograph the wiring orientation. There are typically four wires: two thick wires for the heater assembly (220V/110V) and two thin wires for the thermocouple sensor. Unsolder or clip the old element wires.
If you search for "Schematic 858D hot air station" or "936 clone service manual," you will find 90% of what you need. The Gordak 952 uses the same AC heater control loop as the 858D. Gordak 952 Service Manual
Thermocouple multimeter or dedicated thermometer. Note or photograph the wiring orientation
Reassemble the handle shell, making sure no wires are pinched. Replacing the Diaphragm Air Pump If you search for "Schematic 858D hot air
Disclaimer: Working on mains voltage equipment is dangerous. This guide is for informational purposes. Always unplug your device and discharge capacitors before touching the PCB. If you are not experienced with high-voltage electronics, consult a professional repair shop.
Set the front panel soldering dial to exactly 300°C. Let the iron heat for 5 minutes. Place the tinned tip onto the sensor of your tip thermometer. Look for the small trim potentiometer (labeled "CAL" or "IRON_ADJ") accessed through a tiny hole on the front panel or directly on the internal PCB. Turn the trimmer slowly until your external thermometer reads exactly 300°C.