baribari

I would pay a reasonable sum for a Gem2 module for my Kickr Core loaded with the recent firmware. I take that I would just have to solder the new one in to get speed and power again?

unterhausen

Unfortunately, you need to extract the old firmware.

baribari

Ah, so you can't just change the serial number in the whatever firmware you have to mine?

I would be willing to send the board and pay to have it done if it's not too much, but I am in Japan...

I want to fix it and give it to a friend who needs a smart trainer, since I'm getting a new one.

unterhausen

I swear someone on this thread said that they tried using the firmware from a different trainer, but never checked back in to say if it worked or not.
@rogers2000 is in Australia, so not quite as far as the U.S.

If you can solder the module on, then extracting the firmware seems like it's something you can do. You're going to have to get a module though
Sent you a pm

unterhausen

@dup did you ever sort out your kickr?

dup

Hi,
originally the problem was the kickr showed up on the app etc. but did not show any speed when testing.
As far as an update, I was completely wrong in my assumptions (post #123). The earliest kickr does not use a module. It may be wahoos in-house circuit.
fccid.io/PADWF104/Test-Setup-Photos/Test-Setup-Photos-Exhibit-F-Setup-Photos-rev-1906991
Initially thinking the optical sensor was faulty I replaced it. this is the part but no joy.
uk.rs-online.com/web/p/reflective-optical-sensors/7613984?gb=s
then I almost gave up before watched a video on youtube by hambini about a kickr snap and how the reflective tape on the snap (which toggles the optical sensor) was not optimal and he replaced it with a piece of aluminium tape. I did the same on the kick and used aluminium tape on the white reflective bits in this picture. I had to disassemble the kickr ofcourse.
support.wahoofitness.com/hc/en-us/articles/115001728624-How-to-Clean-the-Optical-Disc-and-Sensor-on-an-Original-KICKR-14
After doing this the kickr started showing speed and I have used it a few times since without any issues. Hope this helps. not bad for a £40 kickr, but still twice the price of the broken washing machine I bought and fixed.

unterhausen

Okay, thanks for letting us know what you found. Might actually be easier to fix an early kickr if it doesn't use a module

wok123

I am going down this repair path too but have hit a snag. After replacing the blown filter capacitor and 3.3V regulator I'm getting low 3.3V line. Checked and the 3.3V line is 5ohm to ground! Drawing about 500mA. Suspect GEM may be the issue as the braking FET measures ok and I can't see anything else that may be causing this. It is a 2019 board, the same as in your video, off a Core. So I won't be able get the firmware out. Is there a generic firmware file that you can edit and add the S/N into? Do you have any other suggestions? Any help would be appreciated!

unterhausen

I think I would remove the GEM and de-lid it to see if you can find something.
Removing the module would help tell if your troubleshooting is correct.

wok123

Thanks for the reply. Yes, that may be the best way forward but I would have liked to get the files out first in case I wreck the GEM. I got a replacement GEM as recommended by rogers2000 so was wanting a plan B in case the original is toast.

unterhausen

I don't know if he has any other ideas, but he isn't on here very often.
I thought the cadence sensor could do this.

wok123

Thanks again for your input! I'll have a closer look at that area as I am hesitant to get into the GEM without downloading the firmware first. I guess the S/N is critical for connection into the Wahoo app.

wok123

Update on my issue. I have managed to replace the GEM2 as described by rogers2000 in his video and I am up and running, well cycling anyway. All for the want of a microcontroller $8.00, 3.3V regulator $1.80, capacitor $0.50, and programming dongle $11.00. Also some very fine soldering!

unterhausen

Great news! Did you get a Gem 2 or one of the alibaba versions? Since it sounds like your Gem module was pulling down the power supply, how did you read the firmware?

BMalone5500

There are indeed some very smart people on here.
I v5 kicker that seems to have similar issues- it started dropping power and now no power output. It does show speed, but anything over 15moh then drops to zero. I have to stop pedaling and slowly bro g it up again- then drops to zero. Will connect via Bluetooth and at this point, I have isolated the problem to the physical unit- not connections or Zwift as it happens on the wahoo app, phone, tablet- etc.
I am assuming that it is something in the sensors or board, but have no idea how to fix it.
I’ll call wahoo, but I am not optimistic

suggestions?

unterhausen

I keep trying to buy a broken unit so I can try to repair it. I think people prefer to throw them away or want too much money for them.

I have heard of this problem a couple of times, where it's still connecting but speed and power aren't working properly. I believe the cpu module is at fault, so replacing it will probably fix the issue.

BMalone5500

I’ll see what KICKR can offer tomorrow. PM me if you are serious about buying one to fix

unterhausen

I would pm you, but you haven't made enough posts to receive it. It's a real inconvenience, but spammers use PM's to send spam, and nobody likes that.
Let us know what they say, there is another person on the forum with the same problem.

ch99_lee

I m having the same issue with my Wahoo Kickr V5 where cadence seem working fine but not the power. I will dismantle it later and check on the GEM version.
Bt the way the Bluetooth LED is not lite up somehow wahoo app still manage to link it.

BMalone5500

Here what I had to do which resulted in wahoo replacing my trainer.

I would like to have you run a quick test using the Wahoo Fitness app so that we can see how the hardware on the trainer is performing. The purpose of this ERG mode test this to isolate the trainer from any potential software issues and allow us to review the trainer control within our ecosystem.

In the results we look for a smooth power profile that shows gradual increases and decreases in power, as changes are made in the Wahoo app. As power changes, we analyze the cadence data to see if the trainer is adjusting the resistance to compensate. Since this test is for diagnostic purposes, it is important that you complete the test as instructed, regardless of the data you are seeing.


Please test using the Wahoo Fitness app on iOS or Android with all additional apps and devices capable of connecting to the KICKR turned off/ closed out. To access this please begin an "Indoor Cycling" workout with the Kickr paired and then swipe the screen until you see the KICKR control screen pictured below. Tap on the ERG tab at the top and follow the instructions below.

(I can’t display the photo)

1) Pair your KICKR to the Wahoo Fitness app
2) Begin a workout in ERG mode and leave the bike in your lowest gear
3) Start spinning, set the power target to 100 watts and hold steady cadence in the 70-100 rpm range for one minute
4) Set target to 150 watts and hold steady cadence for one minute
5) Set target to 200 watts and hold steady cadence for one minute
6) Set target to 250 watts and hold steady cadence for one minute
7) Set target to 300 watts (if possible) and hold steady cadence for one minute
8) Set target to 250 watts and hold steady cadence for one minute
9) Set target to 200 watts and hold steady cadence for one minute
10) Set target to 150 watts and hold steady cadence for one minute
11) Set target to 100 watts and hold steady cadence for one minute

Please provide the e-mail you use to log into the wahoo fitness app, the serial number of the trainer and the date and time of the test. Please also comment on your subjective experiences with the test (did it feel too easy, too hard, just right etc).

unterhausen

What happened when you ran the test? I assume the power didn't hold?

BMalone5500

Correct1- no. resistance.
wahoo was able to read the test and a knowleded it was the unit

ch99_lee

Here’s the main board layout for V5.
I had ordered the J-link and micro-controller.
Will update again.

unterhausen

Thanks for posting. It has a serial port chip hooked to J5. Is J5 connected to anything?

ch99_lee

J5 is the Ethernet port which usually not connecting to anything.
This port is required to connect to a dongle (Wahoo Direct Connect) which need to buy separately in-order to connect to network.