Pinecil died after first use, housing gets very warm plugged into USB
#1
Exclamation 
I have a Pinecil that I used for a single session which is now dead (no LED, no heat up) apart from being able to go into DFU mode and accept flashes.  Support advised me because it does DFU, the unit is working and that I should seek support from the IronOS folks.

It gets warm to the touch even when connected to a PC in DFU mode over 5v USB.

I suspect based on how warm it gets in 5 minutes in DFU mode with no tip, that this unit has a serious problem.   Can someone advise if it's normal for the housing of the unit to reach over 50C when not turned on?   I'm hessitant to leave it connected for too long for fear that it will melt or catch fire.

Here are some images:

Unplugged (Room Temperature is ~25C)

[Image: 120903899-f4964100-c616-11eb-9967-6e8be6798c39.jpg]

Plugged in for less than 30 seconds
[Image: 120903890-eba56f80-c616-11eb-8065-5e7abdf4891b.jpg]

Plugged in for 5 minutes

[Image: 120903898-f4964100-c616-11eb-93d1-521635a230cf.jpg]
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#2
Disclaimer: I don't own one of these devices.

(06-05-2021, 02:21 PM)deftdawg Wrote: It gets warm to the touch even when connected to a PC in DFU mode over 5v USB.

If you think it's faulty, please don't plug it into your computer Smile Although computers tend to have short-circuit protection, it's not perfect.

(06-05-2021, 02:21 PM)deftdawg Wrote: I suspect based on how warm it gets in 5 minutes in DFU mode with no tip, that this unit has a serious problem.   Can someone advise if it's normal for the housing of the unit to reach over 50C when not turned on?   I'm hessitant to leave it connected for too long for fear that it will melt or catch fire.

I would really not expect it to get so hot in just 5 minutes in update mode. The controller and screen should not be drawing enough current to do that.

When powering you should leave the tip connected I believe - otherwise if it is trying to heat the tip it's got nowhere but the handle to dissipate it.

Until you get to the bottom of what is going on, it's a smart idea not to leave it alone!

You should take it out of the housing and figure out where the heat is coming from - I would expect to see a chip getting pretty hot under that plastic cover - should be obvious with your thermal camera.
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#3
(06-06-2021, 03:30 AM)barray Wrote: If you think it's faulty, please don't plug it into your computer Smile Although computers tend to have short-circuit protection, it's not perfect.

Alas, pine's email support said if the device DFUs it's "working", so my only course of action was to attempt to DFU firmware on and hope that somehow fixed it...  

(06-06-2021, 03:30 AM)barray Wrote: I would really not expect it to get so hot in just 5 minutes in update mode. The controller and screen should not be drawing enough current to do that.

When powering you should leave the tip connected I believe - otherwise if it is trying to heat the tip it's got nowhere but the handle to dissipate it.

Until you get to the bottom of what is going on, it's a smart idea not to leave it alone!

You should take it out of the housing and figure out where the heat is coming from - I would expect to see a chip getting pretty hot under that plastic cover - should be obvious with your thermal camera.

Prior to it dying, I tried to turn it on without a tip and the screen just shows a "no tip" inserted icon and won't heat.   No that it's dead with the tip inserted the tip still won't heat up; so that's good I think (fail safe).

I agree, I'm going to have a go at disassembling it...  Maybe the folks at Pine can see something that could be fixed for future batches.
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#4
(06-06-2021, 10:15 AM)deftdawg Wrote: Alas, pine's email support said if the device DFUs it's "working", so my only course of action was to attempt to DFU firmware on and hope that somehow fixed it...  

I know Pine is 'community driven', but it really feels like their customer support needs some work. The device getting crazy hot is not something you've done from just plugging the thing in. There are a few people that have managed to get their Pinecils to internally short too.

I think a reasonable response would be for one of their electrical engineers to ask you to do as I've done, and if you have a voltmeter to probe out some test points from the schematic and check the supply rails.

(06-06-2021, 10:15 AM)deftdawg Wrote: Prior to it dying, I tried to turn it on without a tip and the screen just shows a "no tip" inserted icon and won't heat.   No that it's dead with the tip inserted the tip still won't heat up; so that's good I think (fail safe).

Disassemble it and run it till it gets hot, lets see what is getting hot. There is some good news that you haven't blown the controller and the controller is getting powered. I suspect the issue could be the USB circuitry in negotiating power increase or the power circuitry towards the tip. Both of these could be solved for a few dollars or so.

Also ensure you have a proper power supply that can deliver the voltage and current required to drive the tip. Don't be plugging it into your laptop!

(06-06-2021, 10:15 AM)deftdawg Wrote: I agree, I'm going to have a go at disassembling it...  Maybe the folks at Pine can see something that could be fixed for future batches.

This is exactly why I expect them to pay more interest in the issue - better to catch a small issue now than produce 100k of these devices with defects.

Bare in mind also, that this device is likely a minimal viable product (MVP) for adding faster charging to their more expensive products, such as the Pinebook line and Pinephone. *Any* power supply issue should be really getting their attention.
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#5
(06-06-2021, 03:30 AM)barray Wrote: When powering you should leave the tip connected I believe - otherwise if it is trying to heat the tip it's got nowhere but the handle to dissipate it.

Unless it works unlike all the other soldering irons in that form factor that should be wrong. The heater is part of the tip, so if it isn't connected there's no current running through it and therefore (almost) no power converted to heat.

(06-06-2021, 03:30 AM)barray Wrote: You should take it out of the housing and figure out where the heat is coming from - I would expect to see a chip getting pretty hot under that plastic cover - should be obvious with your thermal camera.

Yeah that'd be interesting. Considering it still works in DFU mode I expect the main processor is still okay, I suspect a driver/transistor has failed closed (they like to do that, MOSFETs especially). That would explain the heat (and might be easily repaired).
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#6
(06-10-2021, 01:56 AM)Kaythe Wrote: Unless it works unlike all the other soldering irons in that form factor that should be wrong. The heater is part of the tip, so if it isn't connected there's no current running through it and therefore (almost) no power converted to heat.

Yeah you're right - I wasn't thinking.

(06-10-2021, 01:56 AM)Kaythe Wrote: Yeah that'd be interesting. Considering it still works in DFU mode I expect the main processor is still okay, I suspect a driver/transistor has failed closed (they like to do that, MOSFETs especially). That would explain the heat (and might be easily repaired).

Yeah that was my general feeling without looking at the circuit PDF or PCB.
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#7
@deftdawg Did you check out the pinecil yet? If you could take a thermal image without the casing on and visually inspect the PCB, that would greatly help in deducing what has gone wrong.
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