# 7Larky SL04 Repair
**URL:** https://foil.zone/t/7larky-sl04-repair/27216
**Category:** Build, Repair & Mod
**Tags:** remote-control
**Created:** [September 21, 2026, 5:11am UTC](https://foil.zone/t/7larky-sl04-repair/27216 "2026-09-21T05:11:31Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@covert](https://foil.zone/u/covert)
#### Post date: [September 21, 2026, 5:11am UTC](https://foil.zone/t/7larky-sl04-repair/27216/1 "2026-09-21T05:11:31Z")
Hi all. I’m new here. I’m a Kiteboarder but only foiled behind a Jetski trying to learn the foil. 7Larky came up at a good price for a person like me with my set of skills.
I got a new to me 7Larky SL04. Couldn’t get the unit to pair with either of the controller so knew I had my work cut out. I dug out the receiver by following the antenna line and pulling of bits of potting one bit at a time. I free enough wire from the ESC to receiver to pop it out.
I took the time to plug a servo tester into the ESC and it worked fine. It’s a Hobbywing XRotor Pro Series 80A HV ESC.
When the receiver powers up and looks for a pair it flashes 2 red LED’s and that’s it. The PCB is the same as pictured on the manual. Not much markings one it.
It has a generic NRF24 module on it with a Hirose U.FL. I think I have one in a part’s box here. I’ll swap that over first.
I’ll get back with my progress.
[edit] module is a AS01-SPIPX. Basically a NRF24 wtih a 20dBm RF amplifier.
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### Author:  [@covert](https://foil.zone/u/covert)
#### Post date: [October 1, 2026, 11:53pm UTC](https://foil.zone/t/7larky-sl04-repair/27216/2 "2026-10-01T23:53:56Z")
I don’t think this repair will go as planned. What I have learned…
I wired up another NRF to the receiver. The RX has 2 LEDs. One LED is on if the NRF is not communicating, probably a critical error LED and the other LED seems to be link status. One of the 3 working TX unit’s I have lights up the link LED and remains lit only while the TX is on, so there is some communication, but does not display any telemetry on the screen. Receiver signal indication remains no signal. It’s like the RX is stuck in the handshake and can’t get past it. Also it still will not pair.
The RX has a switch pads on the PCB. I wired a switch onto that to try to see if it would reset/ rebind etc. No change there.
I pulled a not working TX apart. Removed the faulty regulator that was shorting the power rails. Thermal camera diagnosed that in seconds. I then hooked up a FTDI to the Uart0 on the 15W4K48S4 MCU. No luck there and the STC15 series has no flash read function in the bootloader so I wont be pulling the FW off one of these without serious tools I don’t have (decapping).
What next.. I’ll pull the NRF of the disassemble TX unit and fit it on the RX. I doubt it will work but worth the 5 minutes to test.
I’m exploring TX/RX options now. Either a Maytech V3 or a BreRemote. BreRemote has my interest the most since it is open source and a better radio link.
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### Author:  [@covert](https://foil.zone/u/covert)
#### Post date: [October 12, 2026, 12:23am UTC](https://foil.zone/t/7larky-sl04-repair/27216/3 "2026-10-12T00:23:16Z")
Got the RX working with another NRF module. That’s good news.
I’m not happy with the PWM mapping to the throttle switch. It’s got some dead spots. This has led me to a side quest of building my own receiver. I used Pulseview with a Saleae Logic16. Overkill but works. Only needed 4Mhz capture rate to get a clear reading of the comms. Connected up to the SPI bus of the NRF and grabbed a bunch of packet captures. Looks like I have what is needed to build my own receiver. I’m be taking inspiration from the BreMote and use a ESP32-C3 so I can connect to it over Bluetooth/wifi and configure a throttle curve and other things. With the C3 it will be possible to update over wifi as well. It’s feeding my ADHD monster well for now.
I suspected it was based of some of the open source eSkate remotes but the protocol doesn’t seem to directly match anything I can find.
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### Author:  [@covert](https://foil.zone/u/covert)
#### Post date: [October 13, 2026, 5:16am UTC](https://foil.zone/t/7larky-sl04-repair/27216/4 "2026-10-13T05:16:14Z")
Turns out my NRF24L01 + PA modules are all faulty (5 of them). Wasted a day chasing the problem. They can RX but not TX. I read they can have shorts on them. I’ll try to repair them if anything for testing.
A arduino-nano-rf with a NRF24 onboard came to the rescue in the horde everything electronics box (you know the box. you have one as well…)
Honestly think if anyone else is at this repair / replace stage to look at putting a BreMote V2 in and forget this PoS. But I’m stubborn and would rather fix anything I can.
Good news. Sniffed the NRF24 comms and managed to create code to act as both a receiver and a transmitter. It should work with erayfoil and other cheap Chinese drives with the same remote style.
Where next ? ESP32-C3 with bluetooth settings with the ability to calibrate the ESC max min value and change EXP, might as well make custom throttle curves because…
The ESC in my drive is the x-rotor hv 80A bldc and has the generic ESC calibration feature that can’t be done with the stock remote since the TX wont talk to a just turned on RX unless throttle is a 0.
Might be awhile until the next update. Message me if you want the protocol. I’ll do a doc up on it soon and post it eventually.