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Comment by ruph123 | Hacker News Reader

Is there a more gentle guide with photos how to do it, so once can judge if this is a task that one is able to do?

Just "desolder this resistor and solder it here" does not help me to judge if it is within my soldering ability to accomplish it.

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They have a picture of what appears as the same operation. I'm not confident with electronics at this level.

edit: PINE64: "Also for liability sake: we're not responsible if you break something from doing this. You have the right to mod hardware you bought, but this isn't officially supported. :)"

https://wiki.postmarketos.org/wiki/PINE64_PinePhone_(pine64-...

Looks like an 0805, that's not too bad if you have decent fine motor skills and two soldering irons. If you have enough motor control for decent handwriting you'll be fine, just don't get frustrated and dwell too long, you can practice with the irons off.

you could use an appropriate hot air station + some flux as well I think (and a good pair of tweezers designed for electronics)

Also, kapton tape is very useful if you're afraid of damaging stuff around it

I did the mod with a Pinecil and some tweezers in my kitchen table in 15 minutes. Might look hard but if you have steady hands and a $25 soldering iron you can do it without issues

I think you're off by a lot, the black square at the top left is probably a QFN-24 (i.e. ~0.5mm pin pitch), which would mean it's actually an 0402.

I agree with you, a 0805 would look pretty big there. I think some of those large caps are 0805.

The photo shows an R0402 on it. 0805 is definitely doable by a beginner. 0402 though is at the edge of what could be done without a microscope and not something I’d want to touch with beginner gear.

Ahh yeah I think you're right, I was just going by feel from what I remembered of the board.

This is the operation:

> Desolder R615 0 ohm resistor and solder it to R614, or bridge R614 with solder.

It's just a jumper! This is super easy for a beginner because you only need to desolder and then drop a blob of solder.

Yesterday I encouraged a sharp but inexperienced coworker to depopulate the automatic reset capacitor on an Arduino Nano. He was quite skeptical about the rework, so I went ahead and popped it off with a single iron tip to show him how. I then put the cap back on but offset so that it wouldn't get lost in case we wanted to put it back. I'm pretty sure it was 0402. I'm also pretty sure it was the right capacitor... :-)

I'd say it's actually easier to remove an 0402 than, say, a 1206. Since it's so small, both pads heat up to the point of melting whether you intended to or not, and then the surface tension takes away the component with the iron tip. No need for any specialized reworking equipment. I think 0805 is the sweet spot for easy hand assembly and rework, though.

You don't need two irons, you can touch the tip sideways and it'll melt both pads and the part will stick onto the tip by surface tension.

Thank you!

And uff I don't think I or my TS100 can do it. Might try though as my PinePhone is collecting dust right now anyway.

If you open the phone, take a look at the resistor, and are still not sure, I think the answer to that question is “no”.

(No shame in that and I don’t think photos would change that significantly. But hey, you could practice on something similar but cheaper first to feel more confident, like some broken board you may have lying around or pick up at a thrift store)

This is an excellent answer.

I wouldn't do this as my first SMD project, but if you practice for a bit on SMD based kits you can gain the proficiency required to do it. You may need to invest in a magnifying solution and a very small soldering tip or an air gun and paste. I use a 0.4 mm tip and when I look at it through the microscope while doing SMD work it always looks as though I'm wielding a battle axe to do surgery on a mouse. Usually it works ;)

I would recommend getting a roll of kapton tape as well (make sure it's not counterfeit), and then use that to mask other components so you don't accidentally damage stuff

> make sure it's not counterfeit

'Koptan', no kidding! At least the counterfeiter had a sense of humor.

Good point, thank you I did not know about SMD soldering kits.

desoldering an SMD resistor is actually pretty easy. Just blob some solder on your soldering iron so that the ball on the end of your iron is about the width of the resistor. Then basically place the iron right next to the resistor with slight pressure to the side. the blob of solder will transfer heat to both pads, and it should dislodge pretty quickly (~2s or so). If it doesn't budge, feed in a bit more solder right at the resistor.

It would certainly help to have a temperature controlled iron (but not required). If you are buying an iron new, there is no reason not to buy a temperature controlled one these days. Something like the SH72 is more than adequate for this (~$21 on amazon, cheaper on aliexpress). There are also much better ones available if you are willing to spend some more. (I highly recommend any of the T12 soldering stations ~$50-60 on aliexpress)

As noted in another comment, the resistors on the schematic are specified as size "0402". You can look at this guide [1] for information about surface-mount component size codes, it's quite exhaustive.

Unfortunately, I wasn't able to quickly determine if Pine64 use metric or imperial, and the same code is used for two different sizes (!) depending on that. Nice, huh?

If the schematic is imperial (win) the component is 0.04" by 0.02" (1 mm by 0.5 mm). If the schematic is metric, it is only 0.016” by 0.008" (0.4 mm by 0.2 mm).

[1]: https://www.additude.se/bloggar/thomas-lovskog/smallest-ridi...

You might want to get a little help? My limited experience suggests you'd probably be fine but a little practice helps give a better feel for how much heat you need to pour in. And you probably don't want to let the magic smoke out of your phone while practicing.

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