While using my 858D hot air rework station, I noticed the temperature display had changed from °C to °F unexpectedly. I tried following general instructions online, but the guidance I found (including a Reddit thread) didn’t match how my unit behaved.
What I discovered
On my particular 858D PCB, the °C/°F behavior is not just controlled by buttons. Instead, there’s a hardware switch option:
- The main PCB includes an unpopulated switch footprint labeled S3
- Populating/enabling S3 switches the unit between °C and °F
What I did
- Opened the unit and located the S3 footprint on the main PCB.
- Installed the switch (or otherwise enabled the S3 position as designed for the board).
- Powered the station back on.
- Confirmed the display returned to the expected °C behavior.
