Pinecil V2 randomly enters cooldown mode (pt. 2)

[FalconFour]

Describe the bug
Same as issue #2047

To Reproduce

1. Press '+' to heat up
2. Wait (or try to solder)

Expected behavior
The device should not enter cooldown mode before idle delay. (Or without an error message indicating why it's doing so)

Details of your device:

• Device: Pinecil v2
• Release: 2.23E.4CF7AD8D
• Power adapter being used: Shargeek Storm2 Slim (battery) - USB-PD 90 watts, 20 volts/5 amps, with a 5-amp PD cable

Additional context
This is a new issue as requested in #2047 . Additional answers here:

This may be a newer regression from when this was fixed.

Can you please try changing the USB-PD mode as using a concervative profile may help if its due to voltage drop-out. A Voltage cut-off will trigger a display change if the firmware made the call. It doesnt know if the adapter makes that call.

I've tried setting it to "No Dynamic" - no change.

Can you also in the debug menu check if the Uptime resets when the unit drops out of soldering mode (as this would indicate a restart), where as if it doesnt reset before/after this issue then it would indicate a firmware bug elsewhere. (To allow bisecting what is going wrong here).

Uptime appears to be incrementing. Can be reproduced multiple times while uptime remains further ahead than it was on the last run.

Further additional context:
Though I expect the iron to behave the same at any temperature setting, the issue seems most prevalent at high temperatures - e.g. setting it to 830F for high-power work. In fact, it may be completely related to thermal handling, not even power - but that's why a lack of error message makes it hard to diagnose. I have to constantly check the screen while soldering, to see if it's gone back to cooldown mode while I'm working. When I set to 830F, the temperature display starts vibrating around 810..830 as if it's violently hunting for the temperature, then it goes to cooldown mode without a peep. Set it to 730f, and it does a similar thing, but eventually settles around 725F - unless I start putting some load on it, causing it to become unpredictable again (entering cooldown randomly).

This could just be a case of a bad/degraded/old tip or PID control gone haywire, but a lack of error message certainly leads to being hard to pin down a cause when all I can think is "quit shutting off!!" lol

[Ralim]

Uptime appears to be incrementing. Can be reproduced multiple times while uptime remains further ahead than it was on the last run.

Perfect, this is what I was hinting towards.
So this is a firmware regression, unrelated to #2047, as the power is not resetting to the unit.

Instead a safety is tripping you out of soldering mode. I thought these all triggered warnings but clearly one doesn't.

Please note that you really shouldn't be cranking up your temperature set-point above 400C in normal use. Typically that is a sign of poor thermal contact.

I'm guessing you are tripping one of the runaway prevention's as > 430C ish you are going to be running against the limiter of what the ADC can read (its like 415C + ambient temperature roughly off memory).

I'll have to figure out how to replicate this or have a good squint at the code.

[FalconFour]

Usually I run at high temp when dealing with thick wires (e.g. 8...6 AWG or worse) and need all the power I can get. After many such excursions, I might just be looking at a dying tip. Honestly, I've never worked out what the failure mechanism looks like on these - just keep the tip clean and solder onward. I mostly use a D24 tip but sometimes switch to the "wedge" tip (looks like a spike with a huge thermal surface). Weller kicks arse at high-power/high-thermal loads (I experienced such a system at work, among many others I've used), but the Pinecil works well enough to usually recommend it to anyone.

If I can help find the failure mode that leads to "fault without warning", I'd love to - just point me in the right direction. Might even be worth adding a message to the effect of "your tip might be dying" if that proves to be the case :) :) (I'd love to be better-informed about what a failing tip looks/operates like!)