bench PSU on BAT and GND is just fine, but as soon as you plug in USB, the battery is disconnected from the system to be charged and the system is powered via USB
hmm - perhaps there is something wonky on my board then, because even if I just power from those two pins, my bench supply shows no current draw (and Iâve got the current limit set to 2A) and everything stays dark (unless I attach USB power)
If you want to try leaving xmit enabled on your board (after you get the current code building and running), you can comment out the LORA_DISABLE_SENDING line in variant.h (though the screen update is still really slow because I havenât optimized the display draw stuff yet)
Strange! Can you plz post a picture of the top side?
great! ok, whatâs that component near the two through-holes that have solder on them? it looks like a cap but it should be a 10 milliohm resistor. You know, the 0805 thing near the fuel gauge ic
oh yes - definitely looks like a cap! 
alas I donât know, these boards were gifts from the awesome @einzeln00.
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i know! great guy! I assume you donât have a 0805 10milliohm shunt lying around? If you donât use the fuel gauge anyway you should be able to simply replace this component with a piece of wire (actually you can pick a longer one and coil it together to get 10 milliohm). Current measurements would be incorrect then, but who cares for now?
oh yesssss, the display is working!!
No browning out on the lil board. But also no RF on the output upon sending messages.
Let me check out the fat oneâŚ
ok great! Iâll do that.
youâll need to comment out LORA_DISABLE_SENDING in variant.h
sorry, recompiling
Awesome! Fat one transmits without browning out. Installed on 2 devices and they are recognizing each other. The t-beam nearby is still not joining the party though.
Well done Kevin, very rewarding experience.
So this should be a power issue after all. If it doesnât work from a battery there is maybe not enough bypass caps around the boost converter.
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I havenât investigated but you might try lowering the xmit power by manually hacking line 40 of SX1262Interface.cpp. Perhaps these massive 1W xmits are above what the AGC on the TBEAM SX1276 receiver can cope with at close range?
It sounds like most of the basic progress on this board is finished. Iâll merge into mainline and then churn through bugs and other tasks listed in my work queue (i.e. the RAK815 board etc) for the next couple of weeks. If no one has improved my (crummy) TFTDisplay.cpp hack driver in a couple of weeks Iâll come back to it and make it run fast.
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It didnât work with the 22dbm version either
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hmm - mine happily chats with my tbeams. oh well - it will be solved eventually!
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Ah, maybe you set it up for 915mhz and I have a 868 t-beam?
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ah! thatâs it, if you are building the src yourself it will default to 915 (because thatâs my privileged position 
)
You can either hack line 35 of platformio.ini or in your shell say âexport COUNTRY=EU868â. If you are on linux or mac you should probably add this export line to your ~/.bashrc.
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Palmface. Confirmed with an RTLSDR now. Thank you. I will change that tomorrow and report again.
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Cool! By then you should have a v2.1 board to play around with if the gods of the electronicals are with us. And maybe somewhere on Ali et al. Magically nrf52-based lora boards start to appear
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@geeksville 2 questions:
1 how does line 35 have to look like? default is -DHW_VERSION_${sysenv.COUNTRY} and I tried many different combinations. Obviously I want EU865 instead of US but I keep compiling for 915mhzâŚI also tried to mess with build-all.sh but without success. My Platformio CLI doesnât work under Windows. It does not recognize commands like pio or export. Iâm trying to fix that at the moment.
2 what if I hooked up a NMEA-0183 GPS module to the broken-out UART pins? Does the device expect to find NMEA strings on its UART?
thx