I have recently purchased a couple f9p boards to build a base and rover setup. My first order came a couple weeks before my second one. While I was adjusting settings in u-center, I lost comms on the uart2 port. I had a 100mW air radio connected to it to transmit RTCM.
All was working well for the first few hours and then I lost the uart2 comms. I have used ublox products for many years and am very familiar with u-center and configuring GPS modules. Long story short, I could never recover that port , so I just switched it to uart1 and went from there.
My second f9P showed up, and was set up as a rover. I have put about 3 hours of testing/use on the board when it failed too. This time, I was configuring the module and the usb dropped off. (USB Device Not Recognized) So I tried to reset it with a redboard through the I2C and with no luck. After the module sits overnight, It will power up and communicate briefly on a serial monitor and u-center, then within a minute, the L.E.D lights on the breakout board start to dim and flicker slowly like a voltage regulator is failing and the unit will drop comms and brick. I wasn’t too concerned when the first board was giving grief as i was able to work around it. , but this is now the second time on 2 new modules. I’ve never had any issues with older modules like M8P and Neo M7 … M6 etc. Id like to continue to purchase these modules from Sparkfun, and continue to develop and purchase a couple of a la carte, designs I’m working on, but I’m very concerned about the longevity of this circuit board; for if I start implementing it into a product that I want to sell to farmers across North America, It has to be reliable.
Did I just get a bad batch of Boards? Am i the only one with these issues?
Note: The gnd and 5v pins look like debris between them, but its a reflection from the soldering paste
I have removed all components and just have bare f9p connected to laptop via usb-c cable. Unit powers on for about 1 minute, then comms will drop out. I am almost certain that something is damaged internally.
This does sound like a hardware fault. But I’ve never seen a board act in the way you are describing.
Please forgive me for asking the dumb question, but have you tried a different USB-C cable and/or port on your computer?
If you have time for a little diagnostics, could you monitor the 3V3 pin with a multimeter. Does the voltage collapse when the LEDs dim? That might indicate a regulator fault or something drawing excessive current from it - putting it into thermal shutdown. I always find a “top lip” test handy. Take anti-static precautions, then run the board over your top lip - while powered on. If there’s a hot spot, you’ll find it. (Unless you have a moustache of course!)
To echo Paul, I too am scratching my head. We’ve handled thousands of ZEDs and have found them to be rather difficult to destroy (I don’t think I’ve killed one). That said, anything is possible!
If you’ve got a USB current meter (such as https://www.sparkfun.com/products/15571) they can be helpful detecting shorts or badness. The pics you posted show nice and clean soldering (good work!) but I worry when things are sitting on top of conductive laptops. Avoid shorting out the bottom of the board. What is the enclosure material you’re housing these boards in?
This really is the craziest thing, but I’ve had it connected to a multimeter and laptop for about 15 minutes now with no issues…. :?: I have been able to set update rates and NMEA messages… I really don’t know how things could get better from sitting on the kitchen table for 2 days, but I will re install it back into the receiver case ( abs plastic) and retry it in the field on the rover. Will keep……… look at that!, here I thought I was going nuts!!! In the time it took to type this, it has failed! Looks like regulator is toast. The 3.3v pin just jumped up to 4.56v. Comms lost. Did the lip test, no hot spots. Let me know if there are any more tests I can do to help. Thanks guys
Hi Dave - what antenna did you have attached? TS-Russell had an interesting theory about back driving voltage that could have damaged the ZED. If you’re using a SparkFun antenna, this is not the issue. But if you’ve got a different antenna, that is itself externally powered, then we may have an issue.
Wondering what you found? Did you see anything that stood out? Only reason I ask is because I have another f9p doing the same thing. But this time, after a few minutes, the rtk led goes very dim and the PPS light goes solid. Loss of comms
I have two ZED-F9P modules that I purchased in the middle of the year from Sparkfun to use in a Base Station and a Rover.
I have two Sik 915MHz 100mw telemetry radios, one on each ZED-F9P module, to send and receive the RTCM correction messages.
However, I did not power them with the onboard 3.3 vdc and instead used a jumper wire to provide 5 vdc to one of the UART2 unused header pins and have not had any comms failures since the modules were put into use.
I suspect that the telemetry radios are possibly drawing too much current when operated at 3.3 vdc?
@Dave Eaton - We don’t have the tools to do extensive failure analysis (it’s u-blox’s part) but I remember noting that I had never seen this sort of behavior before. The ZED was powering up but was outputting nonsense. Image below.
