DevTerm A06 assembly report

Finally, I discovered that the batteries I had bought are definitely too big to allow the battery compartment lid to be installed. I really wish there had been more official guidance on the battery. I wound up with the BAK N18650CK, which according to is 18.7mm diameter. I got confused between that battery model and it’s non-button-top version, which is apparently slightly slimmer (18.35). But it seems like these stick out more than a fraction of a millimeter would imply. For now, packing tape must suffice to keep them in place:

I’m trying again with the Epoch 30P (also ordered from 18650batterystore) which claim to be 18.25mm – we’ll see, but the lesson here is that for this battery compartment, diameter is critical, but it seems like there is enough slack in the clips that a slightly longer battery wouldn’t be an issue. Also, after seeing how these fit in the clips, I feel like you probably don’t need button tops, but I’ll find out when the new ones get here.

Definitely would love to hear from folks who have batteries that fit as to what brands and models they are using. And also where they bought from, since I pretty much just Googled and picked at random.

Also, it seems like pretty much any available battery that I’ve seen is going to be fine as far as the continuous discharge rating, given that the smallest I’ve seen are still like 5 or 6 amps? Given that the instructions recommend at 2A USB-C charger, I’m guessing that’s well above the draw current to run the system.

Anyway, the upshot is that my DevTerm booted right up, and seems to run just great. I can definitely feel the heat coming off the bottom of the case where the mainboard is located, so it’s obvious that heat sink is needed.

Now to go explore the software side of my new toy!


The blue pad is a thermal pad, commonly found in many components like GPUs

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I really hope there is official guidance posted soon about the heatsink.

Thanks for clarifying these issues @rafial, as I’ve seen hints of these in other forum posts but so far there hasn’t been any acknowledgement or update to the instructions so most folks will have to make the same mistakes over and over. That could be especially bad considering how it sounds like it’s easy to accidentally bend the metal around the screen, have batteries ready to go that won’t end up fitting, etc. The heatsink is particularly troubling. Sounds like the blue backing was just trash (covering the adhesive), but @Petrakis suggests it might be a thermal pad. Surely Clockwork folks know how it should be installed, since they included it. And if some folks don’t install it at all since it wasn’t mentioned, they might end up overheating their devices. :frowning:

As a side note, it would be great to have a thread where folks post what batteries they are using that work too. (And also batteries that are known NOT to fit.) Even if Clockwork can’t comment on them or suggest any, it seems like a good thing for the community to do to try to help each other out.


A similar thread about thermal printer paper would help too. Would be great to see a list of known working paper and known paper that doesn’t fit or is too thick to work, etc.


Yup. To further clarify, the blue is a plastic film, which when peeled off reveals a thin sticky white pad on the flat side of the heat sink. Given that there was no other obvious way of mounting it, I assumed that the white pad was there to glue the heat sink on to the CPU.

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I bought a couple 50’ rolls from Adafruit and they seem to fit perfectly: Thermal paper roll - 50' long, 2.25 wide : ID 599 : $1.95 : Adafruit Industries, Unique & fun DIY electronics and kits


Almost everyone in this forum says only the length of the thermal paper, but I only could find vendors that specifies only the diameter in my country.

This helped me a lot. I bought rolls of 40mm in diameter. It fits well in the tray. I haven’t tried the 45mm one, but I think that it wouldn’t have fit in there.

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its 57mm * 40 mm probably. I use 57*35 papers

I second this. I don’t have batteries yet though. I’m really hoping that the ones I settled on actually fit and work.

So to be clear, the blue film is necessary? how is the heaksink then secured to the compute board?

You can throw away the blue film once you peel it off. The important part is just that you peel off the blue film to expose the sticky white pad underneath, which you stick onto the chip. That lets the heat sink can do its job keeping the chip cool. The picture from @rafial above (DevTerm A06 assembly report - #3 by rafial) should be the end result - you see the fins. The white sticky pad (under the blue film you throw away) is underneath, stuck to the chip.


Ok this is what I thought, there’s a bit of misinformation above. Thanks for the clarification!

I assembled mine today too. Some notes:

  • I put the antenna on the other side of the plastic. This caused problems for fitting in the battery board. It was not clear to me how to do it from the manual. Now it’s stuck there forever so… oh well?

  • The ribbon connectors were not clear also. You have to flip the little tab UP first before you can slide in the ribbon cables. I tried pulling the tab out, and one went flying across the room. Fortunately it went back in fine.

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If anyone has one of those guns you aim at a place to get thermal readings, I’d be curious to see where the heat is generated.
I accidentally left my gameshell in a bag while doing an overnight compile, and it rewarded me with a lovely melted heat map:
At least I could identify where the hot spots are!

According to official photos, the heat sinks are installed like this:

I’m assuming that this is an A04 and an A06 unit; with the latter having a larger heat sink.

The main CPU is raised up relative to the other soc components, meaning that after adhering (yes I removed the blue film :)), only that would be making contact.

In retrospect I’m wondering whether or not I should have perhaps applied some thermal pads on some of the components. The last thing I want to be doing is applying something that acts as an insulator, or worse still, has the CPU transferring more heat to, than is dissipated.

That’s something in general I fear regarding the heat sink. My fan is barely ever on. This means there’s no aid flow. Would the heat sink merely be insulating, with no place for the heat to be exhausted from? The fins look far too shallow and thick to be conductive. I would love fo see thermal readings with and without the heat sink applied.

On the note re: the top clip not closing properly, I initially got that. I had a similar problem with my DEOT shell for my gameshell, but not my clear one. Like gunpla, I find the clear pieces to be harder and less prone to warping, compared to the opaque ones. I got an opaque grey devterm, so assumed this to be the case. However it seems the OP has a clear one.

I came up with a solution when I built mine. There was a spare power button. The orange transparent rectangle. This was EXACTLY the right size to be uses as something to reinforce the retaining tab. That is to say, it wouldn’t push the chassis out, deforming and putting pressure on anything, but also wasn’t too small, as to end up rattling and falling off. It simply did its job of keeping things in place.
This is something that all Devterm owners should have, so should be a universal fix. You could even double sided tape or glue it down if you wanted to. I haven’t, but then again I’ve only owned mine for a grand total of one day.
Here’s some pics of the mod:
The piece


The final result

I think this must be the A06 rite of passage: feeling this is easy, seeing the lcd frame bend and becoming overly cautious, get through everything with the instructions at your side but struggle aligning the top case, realise the heatsink isn’t in the instructions, open it back up to apply the heatsink, struggle to align the top, open it back up because you just noticed when you applied the heatsink you dropped the power button/one/both side panel(s), realise you are now expert at getting the top on, profit


The pad which is on the heatsink is the equivalent of thermal paste, so do not use thermal paste.

There is another reason to not use thermal paste, the heatsink will not stick anymore.

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I was thinking keeping the adhesive where it interfaces with the main processor, and since the heat sink doesn’t actually make contact with the other onboard components, bridging the gap with thermal compound; not paste.
This kinda stuff.

I would probably remove part of the double sided adhesive that isn’t making any contact with anything, since I have no idea how two different thermal compounds interfacing would affect conductivity. I’d assume negatively!

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I wondered if my batteries were to large too, at first, because I expected the battery door to slide on like many battery doors do, but then I noticed that the battery door has a bulge in it, so I placed the battery door over the batteries and was able to slide the door into place anyway. From the look of your photo I wondered if you had the same issue as I did.

Yes, I actually made the same discovery later. My door does fit with the original batteries I was using. Thanks for providing the follow up tip.

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Finally I found time and build mine yesterday. After all the information about broken screens and so one did not expect it to work :smiley: but happily it looks that most of the things work (os, network , sound, screen, keys etc)

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