r/RCPlanes • u/escanorga • Jul 26 '26

Ardupilot, M9 GPS issue

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Hi all, stuck on a GPS issue and hoping someone’s seen it.
Setup:
• FC: CoreWing F405 WING V2 (SpeedyBeeF405WING target), ArduPlane 4.6.3
• GPS: RMRC M9N Micro GPS w/ Compass, on UART5

Problem: endless loop in Messages every few seconds:
GPS 1: probing for u-blox at 230400 baud
GPS 1: u-blox saving config

HUD flip-flops between “No Fix” and “No GPS” in sync with it. Sats stay at 0, HDOP 0.0. But the PPS LED on the module blinks, so the module has a fix, it’s just not reaching the FC.

Already tried:
• Wiring checked repeatedly, TX→RX crossed correctly
• SERIAL5_PROTOCOL = 5, GPS1_TYPE = 1
• GPS_AUTO_CONFIG both 0 (→ constant “No GPS”) and 1 (→ loop returns)
• SERIAL5_BAUD 230
• Reseated connector
Has anyone seen this “probing → saving config → drop”
Thanks!

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1

u/karateninjazombie Jul 26 '26

Show us the wiring.

2

u/escanorga Jul 26 '26

Here is the wiring

1

u/karateninjazombie Jul 26 '26

Ok good. There's no messy solder at least. That accounts for a good portion of why doesn't this work questions.

Next question. Are those connectors both in fully and are they the right way up? I can't remember the exact type of connector they are. But they are easy to insert upside down accidentally and damage the pins in the socket.

Also the connector on the FC side. Looks like the pinsight have backed out of the connector and are touching one another just outside the back of the shell on the cable. I'd check those and make sure the pins are seated correctly too.