rogers2000

In my case, there was a power surge, evidenced by the smoothing capacitor that had blown. I believe this led to the GEM2 module malfunctioning, it appeared completely dead, yet I was able to extract the firmware when connected to a J-Link type programmer and re upload this to an Ali express module, make the connections, and it has been working fine ever since. Also replaced the power line capacitor.

rogers2000

Any generic module should work, provided it has the nrf52832 IC, a 32MHZ CPU crystal, and either a 32KHz crystal for the clock or you will need to break out 2 more pins to the 32KHz crystal on the main PCB. In my case, the Ali express clone had a clock crystal which saved me 2 breakout wires. You will need access to the following pins: P0.26 (red LED), P0.27 (blue LED), XL1 & XL2 if not using an internal 32Khz crystal, P0.08 (brake), P0.29 (temp), and VCC and GND, (and SWD, SWCLK to program). Unfortunately I don't have a picture of my final fix, only the temp fix with a sparkfun dev board while I was waiting for the Aliexpress module. For a future repair, I would try and buy the module from North Pole that unterhausen linked, or another aliexpress module and place a small piece of blank PCB as a standoff, epoxy to the main board and solder the correct wires. There doesn't seem much else to repair the PCB, all the other faults could only be a MOSFET, power regulator, blown cap or maybe a cadence, temp sensor fault. All these are easy to repair and I'm surprised that Kickr doesn't offer a repair service. Maybe the cost of shipping is not worth it due to the weight?

Anyway I have repaired electronics as a full time job for a long time, I realise the above paragraph is beyond the scope of normal users, but perfectly within the capability of any decent electronics technician. I am happy to assist repair as I hate seeing products go to waste. I should be at the 10 post limit now so I will see if I can flick you a PM DGhostRider

rogers2000

Faulty GEM2 connected to programmer to extract firmware. Firmware is in location 0x0 - 0x7FFF and UCIR factory setting are in location 0x10001000 to 0x10001FFF

Kick Core mock up including aliexpress module, bluetooth and power LED's, button to replicate cadence, thermistor and programmer

A working Kickr Core with a sparkfun NRF52832 dev board

DGhostRider

There are some insanely smart people in this thread!!

unterhausen

So do you think the firmware could be read with the module in-circuit?
Thanks for the awesome post.

rogers2000

on-board programming connections
Yes it should be possible to read the memory while the chip is connected. Just connect the pins above to a j-link such as https://www.aliexpress.com/item/1005003620592002.html

The j-link commander program will put the chip into programming mode and use the 3 pins (SWD, SCLK, GND) to access memory, which it can all do in-situ

ClassicSmith

Wow very impressive thread, I have a 16 kickr with no lights powering on.. There is heavy resistance on the flywheel when plugged in and none when unplugged. Still to remove the flywheel to get to the board to take a look….

rogers2000

oh yea there does seem to be a lot of issues with the 16' core. if there is maximum resistance when the power is on, then it means the mosfet controlling the brake is getting the signal to go fully closed and hold the brake line. basically the braking works by connecting the lines coming from the coil, and this creates an opposing magnetic field when the rotor tries to rotate. it is controlled by the microcontroller, which controls a transistor, which controls the mosfet. it normally uses PWM to control the amount of resistance. If either the mosfet, the transistor, or the microcontroller are faulty then it can lock the brake on. in your case, and judging by other 16' cores, I'd say the microcontroller is faulty and it is holding the brake GPIO fully on. It isn't too bad to pull the bearing apart, just be mindful to lever the hard outer bearing, and don't hit the inside rim which is soft aluminium where the bearings are held. Have a look for any obvious burning / damage, but it is more than likely going to require a new micro controller

ClassicSmith

Managed to get the flywheel off without too much trouble. Board looks totally clean with no signs of burning, so as you suggest may be the micro controller.

ClassicSmith

Sorry I haven’t seen micro controller mentioned earlier is this the entire raised board with ‘GEMSRB02‘ or something else? Is it something that can be replaced without needing to extract firmware?

rogers2000

the microcontroller is part of the small raised board, under the metal RF shield. the board is called a GEM2 module, which consists of an NRF52832 micro controller, a few passive components and an antenna for bluetooth and ANT.

This whole module will need to be replaced (or take the shield off and replace the nrf52832 if you are very skilled..)

There is no way to get a new gem2/micro that is programmed from the manufacturer (as far as I know..) - you will need to extract the firmware off the old board and upload it to a new module

FredW

MY Kickr 17 was accidentally plugged into a 24V power supply. If I can get the PCB out is anyone offering repair? Wahoo denied me.

rogers2000

yep, I'll flick you a pm

Eissack

First of all I wanna thank you for your detailed explanation. With your help I managed to extract the firmware from my damaged nrf52832 and flash it onto a aliexpress replacement.
However I think I did something wrong. I am not sure if my firmware was somehow corrupted, since the while the kickr is more or less functioning, it does all sorts of weird stuff. Do you think I could send you my firmware dump and you could crosscheck it with yours? The Board revision seems to be the same from what I can tell.

Elrikos

amazing stuff. i have a dead kickr board sat in front of me and im very keen to talk this through with you, when i get to 10 posts!

brownhound

Wow - this is a great thread. My Core stopped transmitting data. Looks like I need to find an electronics repair shop and see if they can decode the people who are diagnosing the problem and likely repair.

Wahoo only says it will replace units now, not fix. My unit is old enough that not covered by warranty (and bought from a now defunct store). Incidentally, to be covered by a warranty one should provide picture of original receipt. Which I don't have.

Smackpappy

I did the unthinkable. I plugged in a power supply from a Saris into my wahoo. It was a 48v ps. Now I get no lights and it feels like the break is constantly on.

Based on what I read the PCB is fried. I can't believe it. I tried to message the one person here that says he can repair.

I'll call wahoo tomorrow but I have low hope. A good news situation would be getting a new board for 200 bucks. Not sure if that is an option or not.

what have others done in this situation

Smackpappy

Im a newb so I can't message anyone. This is only my second post

unterhausen

If you are talking about @rogers2000, he has only ever posted in this thread. So he's not on the forum very often. I'm not sure anyone in this thread has said what gets fried when the voltage is too high.

What version of kickr do you have?

For anyone that came here because it's the only place on the web talking about repair, please take some pictures of your control board and upload them to an album on your gallery. Don't forget that it looks like it uploaded, but you still have to hit the "upload" button for some strange reason. Then post in this thread and someone will rescue them. Newbies can still post a visitors message on another user's profile. You reach their profile by clicking on their username.


This thread is such a mess from people multiply posting to get to 10. I have been tolerating that because people need help, but it certainly makes the thread a mess. It's against the forum rules, we have the 10 posts rule to keep spammers away. The rule works, and I'm somewhat unapologetic that innocent people get trapped up in it.

pixjnr

Gday All - really glad I found this thread. Can someone provide some advice on next steps? I plugged in a 48v charger and appears the capacitor blew. Can I replace just this and try to power it on?

rogers2000 - Are you doing repairs at all? I am located in Aus and could use some assistance.

I am unable to post photos since i have less than 10 posts.

Cheers, Simon

pixjnr

Smackpappy - any luck with Wahoo?

unterhausen

Reprising. My last post covered the issue with uploading pictures. You can't post them here, but you can upload them to a album on your gallery. Don't forget to hit the "upload" button, on the desktop web version its at the upper right. If you post here that you did that, I will post them here for you. And also what version of kickr do you have?
It seems unlikely that the cap was the only thing burned, but I suppose it's worth a try.

pixjnr

Thanks unterhausen . Appreciate your reply. I tried to create an album, however after clicking Profile > Album > Create Album > it redirects to a page that says " V Bulletin message - Our records show that you have already registered under the name of pixjnr. If you have lost your password, click here. If you would like to modify your profile, click here ". This even when I am logged in. I tried a couple of other methods (ie; via gallery links and clicking on the upload photos to community button) but it is the same message.

I've added a link to my profile under the socials tab to a flickr folder. There are three photos in there. I hope this is okay - but if it breaks forum rules or anything I will take it down.

So photos are at > User Profile > pixjnr > Social Profile > Home Page > Flickr Link.

Cheers, Pixjnr.

pixjnr

Quick question. Are the circuit boards between kickr core, kicker v5 etc the same?

Smackpappy

I actually ended up sending my card from the US to NZ for rogers2000 to look at. In the end he was able to replace all broken bits but was unable to get my 2016 firmware back installed. He did get 2018 firmware installled on board. So it's a sort of good news story. Rogers2000 was awesome to work with. Very professional.

I just need to figure out what happens when u run the wrong version of firmware on the trainer. I didn't put it back together yet.


good luck everyone. He proved a fried board can be fixed.