858D hot air station provide air at 200 degree instead of 500

[corrize]

Hello, I noticed that was become almost impossible to desolder component with my hot air station. I measured with meter : air at output is at 220 degree celsius max, even set at 500 degree. So something is bad. Maybe temperature probe inside ?
Not yet disassembled, have you see some « well know » ou frequently issues to this sort of tools pls ?

[stj]

post a picture of the board, i have some schematics

[diif]

Inspect the heating element when it's on. I must have knocked my nozzle as the element had become a little tangled and wasn't heating evenly/fully.

[corrize]

I disassembled and there is nothing inside. The box seems good. The issue come probably from gun. That could be the heating element indeed, I will check that.

[corrize]

I disassembled the gun, nothing obvious.

I see a bimetal, probably good. Thermal probe taped with heating element.
That could be wire of eating element touching other and reduce heating capacity ?

[stj]

when you turn it on, do you see the temperature rise on the display?
if yes then it could be the feedback circuit.
(we can check that with a soldering iron)

also, look at the aviation connector contacts - those connectors arent really rated for this type of power

[stj]

on the board under c3 is a transistor or something - has it got a hole in it or is it the camera?

[corrize]

I checked, it’s factory mark, not a hole. The temperature rise on the display. I can’t check the connector, the front cover is very hard to remove. I can’t pull button.
I don’t know electronic for heat. It is alternat voltage feeding the gun ? And what’s increase the heat when I turn the button, voltage or current ?

[stj]

the heater is mains voltage 230v, the heat is controlled by the board pulsing the power and an ajustable speed.

[harp]

Check resistance of disconnected heater element, and compare measurement with same end on pcb board. Maybe some wire connection has loose and warming up.
Resolder all pins of triac and tracks from mains to heater on pcb, make it flooded with solder.