libera/#neo900/ Tuesday, 2019-05-14

slobberDocScrutinizer05: sooo can i hit up your "...source of at least 200 devices in pretty much mint condition"?01:18
Oksanasicelo: Great to hear that USB problem is fix-able by somebody without soldering experience?01:41
OksanaDocScrutinizer05 : Small soldering iron, or better hot-air reflow... Will see what is available at makerspace. Watched the video a little, now I know that solder is not to be put at the tip of the iron - no idea how to clean tip of the iron though. I am guessing that soldering micro-USB port is quite different from soldering a through-hole chip? Reading up...01:42
Joerg-Neo900yes, soldering the USB pins is quite difficult particularly to simply get by. For the reinforcement (soldering down the sheath to PCB) you need a rather large (80W+) soldering iron since the PCB has large copper planes that dissipate all heat01:58
Joerg-Neo900for the pins hot air reflow with pre-wttwed/plated pads and pins and a lot of excellent flux, or even better using solder paste, is the better option for sure01:59
Joerg-Neo900using soldering iron you'll need a very slim tip and yet you gonna have to cut and remove some metal sheets to get by02:01
Joerg-Neo900or the hacker approach: use 0.1mm diameter varnished copper wires maybe 6mm long, to connect USB jack pins to PCB pads, then *carefully fold the wires back to place the USB jack into place and solder it down mechanically02:03
OksanaDissipate all heat, to where? Don't want to burn something fragile like camera module...05:25
* Oksana might have contact with a friendly soldering person at local makerspace, will bring an old Sony Ericsson mobile for starters - its charging port is falling off, and the pins are fairly thin as well
DocScrutinizer05Oksana: you ideally remove the cam module prior to USB fix. Or at very least cover it with e.g. Kapton tape. The groundplane whare you solder the jack shroud to will not heat up so much that it could damage other nearby components. That#s actually the cause of the problem that it spreads the heat and thus reduces it to levels that are harmless for components but not suitable for soldering a proper joint05:41
DocScrutinizer05you need a soldering iron that has sufficient thermal mass or power to heat up the soldering joint within less than a second so the heat doesn't spread much into the surrounding area05:43
DocScrutinizer05several folks done USBfix before break and it's really simple and low risk, you just need a decent literally heavy soldering iron. Or e.g a Ersa Analog-60 (sufficient Watts, the "60" here is err whats the opposite of exaggeration ?) which did the job great for me05:48
* Oksana has mostly N900s with already broken-off USB ports - there is one N900 with working USB port but it has no cellular connectivity05:50
* Oksana should find where this N900 with-no-cellular is - could perhaps salvage cellular antenna from it, because my current N900 has cellular antenna worn out to the point of copper being visible with green rust05:53
DocScrutinizer05green rust is actually a massive issue. You know skin effect?05:55
DocScrutinizer05there's a reason to have antennas rather silver/gold plated than green rust05:56
DocScrutinizer05thanks to skin effect all but surface and maybe a few micrometers deep into conductor from surface doesn't matter at all - high frequency RF current only flows on the conductor's surface05:58
DocScrutinizer05iirc it's caused by eddy currents and the magnetic fields they create05:59
DocScrutinizer05but if I had to guess, I'd suspect any problems you encounter with this antenna are first and foremost caused by contact failure at the point where the C-spring touches the antenna conductor06:01
DocScrutinizer05when the antenna builds up green rust, the chances are it also builds up oxides and other "dirt" at that point between antenna pad and C-spring06:02
DocScrutinizer05somebody (in here?) had exactly same problem a few days ago06:02
DocScrutinizer05whoever you been, could you please report back opn results of your "fix"? :-)06:03
siceloOksana: it definitely is possible. obviously one must be careful. i watched some youtube videos before doing it10:17
DocScrutinizer05ZombieLoad yay20:06

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