Hot air station warms up but bails out halfways (Atten ST-862D rebadge)

[trondl]

Hi!
I have an RS Components 2024489 station, which is basically an Atten ST-862D.
It worked fine for over a year of random use (not daily).
It then started to heat up as usual, but when halfways into the ramp up, it beeps and cools down again.
Bought new heating elements from a different brand (MULTICOMP PRO MP740787) as RS had a significantly longer delivery window.
Worked fine for some hours.
Now it's the same again.

Any suggestions?
Usual suspects?

The unit hasn't seen rough usage, and has been IMO treated with care.
I do have one more fresh heating element if you believe I've been delivered a dud.

[wasedadoc]

Have you ascertained whether the elements go faulty or is some control ciircuit cutting the power off?

[modoran]

Maybe the button on the handle is the problem, or some wires became loose.  You could've been buying 2 original Atten for the price of one RS rebrand.

[trondl]

Maybe the button on the handle is the problem, or some wires became loose.  You could've been buying 2 original Atten for the price of one RS rebrand.

I opened up the handle to inspect the switch.
It seemed functional, but I gave it some contact cleaner to be on the safe side.

After reassembly, all was fine again!
May have been a slightly off centre placement of the switch that caused the whole issue.

Thanks a bunch!

[trondl]

Not so fast!

It is stable when the handle is horizontal.
Once I tilt it vertically-ish, it cuts off.
I've tried wiggling the tube at each end without causing any issues.

Hmmmm.

[BlownUpCapacitor]

If I recall correctly, there is a reed switch in the heat gun that turns off the heater when in the holder. That reed switch may be faulty. Check that.

[trondl]

If I recall correctly, there is a reed switch in the heat gun that turns off the heater when in the holder. That reed switch may be faulty. Check that.

It seems like it is definitely the reed switch.
When I hold the handle very horizontal, it works.
Only at an angle is the issue.

Is the reed switch at the socket end somewhere?

[perieanuo]

you must have a sensor in your handle, tc or ntc/ptc or whatever, he can give the same issue (well, him&his harness).
reed activating only horizontal without some external magnetic stimulus is very odd imho. my primary suspect is the temp sensor or around him

[trondl]

you must have a sensor in your handle, tc or ntc/ptc or whatever, he can give the same issue (well, him&his harness).
reed activating only horizontal without some external magnetic stimulus is very odd imho. my primary suspect is the temp sensor or around him

It is perfectly stable in temperature when the handle is fully vertical or horizontal, not at an angle.

[perieanuo]

so measure at the end of the harness on main pcb-side, you'll get if heating is powered and if temp feedback is ok. then you know where to look