# RTK Express USB Serial Not Connecting **URL:** \ **Category:** SparkPNT / Consumer Products\ **Created:** [February 18, 2025, 4:29pm UTC](https://community.sparkfun.com/t/rtk-express-usb-serial-not-connecting/63485 "2025-02-18T16:29:51Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Brack](https://avatars.discourse-cdn.com/v4/letter/b/5fc32e/32.png) [@Brack](https://community.sparkfun.com/u/Brack)\ **Post date:** [February 18, 2025, 4:29pm UTC](https://community.sparkfun.com/t/rtk-express-usb-serial-not-connecting/63485/1 "2025-02-18T16:29:51Z")
Using an older RTK Express, Firmware @ V2.4. Recently had some issues with it. USB Serial is not working on either port. Had to replace the LDO to fix charging issues, but the USB serial was not working prior to that issue being fixed. I have confirmed my USB Cable does work, it connects to serial with an Adafruit Feather. Has anyone had this issue? ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [February 18, 2025, 9:15pm UTC](https://community.sparkfun.com/t/rtk-express-usb-serial-not-connecting/63485/2 "2025-02-18T21:15:06Z")
I would still try another cable and usb port, just to be sure (sometimes the mating can matter) Also ensure the drivers are current [How to Install CH340 Drivers - SparkFun Learn](https://www.sparkfun.com/ch340) , and test that the full 5v is being delivered with a multimeter if possible If nothing changes still, you might want to [try a factory reset over WiFi](https://docs.sparkfun.com/SparkFun_RTK_Firmware/menu_system/#factory-reset) ---
**Author:** ![Brack](https://avatars.discourse-cdn.com/v4/letter/b/5fc32e/32.png) [@Brack](https://community.sparkfun.com/u/Brack)\ **Post date:** [February 19, 2025, 1:28pm UTC](https://community.sparkfun.com/t/rtk-express-usb-serial-not-connecting/63485/3 "2025-02-19T13:28:01Z")
Unfortunately, none of these worked. I have tried several USB C cables that I have confirmed work on other boards and devices. The Voltage is 5V. Drivers installed, uninstalled, installed. And factory reset complete. I was unable to get anything to react to the device being plugged in. ---
**Author:** ![sparky](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/sparky/32/6021_2.png) [@sparky](https://community.sparkfun.com/u/sparky)\ **Post date:** [February 19, 2025, 3:09pm UTC](https://community.sparkfun.com/t/rtk-express-usb-serial-not-connecting/63485/4 "2025-02-19T15:09:42Z")
Is the device charging? If it is, then there is at least a 5V/GND connection through the USB C connector(s). If it’s within the 1-year warranty you’re welcome to start an RMA and we’ll have a look and get it fixed for free. If you’d like to take it apart and have a look, that may shed some light on the problem as well. The USB connectors are independent from each other (they wire to separate devices internally) so I’m not sure what would cause both to fail. The first thing I would check is the rear pins on the USB C connector. Also, and I’m reaching here - USB C connectors have duplicate D+/D- pins to support the ability to plug the connector in upside down. This means that if the solder connections on one set D+/D- pins have failed, you can turn the USB plug on your cable upside down and you’ll connect to the other, redundant pair. ---
**Author:** ![Brack](https://avatars.discourse-cdn.com/v4/letter/b/5fc32e/32.png) [@Brack](https://community.sparkfun.com/u/Brack)\ **Post date:** [February 19, 2025, 3:18pm UTC](https://community.sparkfun.com/t/rtk-express-usb-serial-not-connecting/63485/5 "2025-02-19T15:18:54Z")
Yea I am wholly uncertain if its within the 1 year warranty. I took this project on from someones project that had been abandoned a while ago. I had taken the device apart to replace the LDO to fix the charging issue, which it is now doing correctly. I checked the pins for the USB-C connectors and nothing looks out of sorts. The connections to the components after also do not appear to have connection issues. ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [February 19, 2025, 10:16pm UTC](https://community.sparkfun.com/t/rtk-express-usb-serial-not-connecting/63485/6 "2025-02-19T22:16:30Z")
If you have any associated email/company name/purchaser name, feel free to DM me and I’ll look for an order history