Trying to bring a Wahoo Elemnt back to life
 

A buddy had troubles with his Wahoo Elemnt, and Wahoo was nice enough to replace it. They didn't ask to have the bad one returned to them, so he gave it to me to open up and perhaps fix whatever was wrong.
Cool!

I should say that I don't know what model this is:
https://live.staticflickr.com/65535/...41bb25_c_d.jpg


When the device first turns on, it can generate a couple of screens of images, with varying amounts of corruption. Here's a link to a video of the power up sequence..
https://drive.google.com/file/d/1IN8...ew?usp=sharing

It seemed like there might be a bad connection to the display that might be improved by touching up some solder joints, so it seemed reasonable to open it up and see what's inside.
Before doing that... I figured I should see whether the firmware could be updated. I assumed that Wahoo would have already instructed my friend to do this, but I looked up the process anyway. It turns out that firmware updates have to be done via the device's wi-fi connection, and without a functioning display, there wasn't a way to do this.
Okay... then let's open it up!

The back is held on by T6 screws. These screws have small o-rings under the heads to keep moisture out, which is a good sign.
With the screws out, the front and back halves look like this:
https://live.staticflickr.com/65535/...bd2969_b_d.jpg


Two flex strips connect the halves.
One looks like the USB connection, while the other might be some sort of battery monitoring signals. The battery power is transfered through the spring tabs at the top end.
The electronics is largely convered with shields to contain the RF (radio frequency) energy. The smaller shield has a trace coming out that is labeled "BT/WIFI", which means this goes to the bluetooth and wi-fi antenna. There is a little coaxial connector located on the trace, presumably to make it easier to check transmitter/receiver on the production line.
On the upper left of the board is another trace and coaxial connector, with the label "GPS" nearby. It's a good guess that the GPS electronics is under the larger shield.


The flex strips from the back half use little snap connectors to mate with the front half. These are easy to remove.
https://live.staticflickr.com/65535/...8404e9_c_d.jpg


on the left side of the front half are two connectors that lead to the display assembly. One uses the same style of snap connector used in the previous photo. The other flex strip connector is obscured by the foam pad stuck on top of it.
https://live.staticflickr.com/65535/...01aeca_c_d.jpg

Removing the circuit board and display from the plastic housing reveals the display and associated switches and LEDs. There's not much there that a person could tinker with.
https://live.staticflickr.com/65535/...3bb094_c_d.jpg


The flat flex going to the mystery connector seemed like the most likely source of troubles at this point. The flex strip was easy to remove from the connector and didn't show any obvious damage. A mechanical pencil with 0.5mm lead is shown holding the flex strip down...
https://live.staticflickr.com/65535/...5233f6_c_d.jpg


Removing the foam pad from the connector showed what appeared to be a latch in the upright position.
https://live.staticflickr.com/65535/...1d337c_c_d.jpg


There does appear to be some damage to the latch, though.
https://live.staticflickr.com/65535/...9977e8_c_d.jpg

I'll have to continue this in a second post...

Steve in Peoria

Flipping the latch down seems to require a bit of force, and makes the flex harder to move.
https://live.staticflickr.com/65535/...bf7554_c_d.jpg


did it fix the problem??
umm... nope.
https://live.staticflickr.com/65535/...62f33d_c_d.jpg


It would be fun to get this thing working, so let me know if you've got any viable recommendations.
If not, I'd be happy to donate the parts for the cost of shipping, in case someone has a use for it.

Steve in Peoria

I think you've reached the point where you understand why Wahoo didn't ask for the unit back to be repaired. On the good side you've got what looks like a good spare battery!

Judging by your last photo, I'd say you should be looking for the Wahoo Secret Decoder Ring. :lol:

Oh well, cool to see the innards anyway. Guess you could try banging it on the workbench a time or two.:foo:

I'll have to give that some thought... I've had a variety of projects that started with some interesting part and I had to figure out some way to use it. :)

Steve in Peoria

there must be some phone app for that, right??

In the meantime... I wonder if anyone has scratched up the front screen on their Wahoo gadget and could use the front half of the housing?

Steve in Peoria

I might have to get the meter out and see if I can figure out what's not making a connection. If I haven't angered the gods of the electrons, I might be able to touch up a solder joint and get it to work.

Steve in Peoria

Interesting about the connector not being latched. I assume that's what was wrong. At this point you might have to replace the connector in order to get it to work properly.

that's certainly a possibility.
I was looking through Digi-key trying to see if I could find a similar connector, and there must have been a few hundred pages of results. Not exactly sure how I'd find an equivalent. Just look for anything with 10 pins with 0.5mm (I think) spacing?

I need to see if I can meter out the connector... i.e. from the connector's pads to the flex strip's conductors. If that's okay, then the problem might be where the flex terminates somewhere within the display assembly.
Probing the connector pads might be a challenge, if only because getting probes onto those little pads might be tough. TBD. :)

Steve in Peoria

A guy who worked at Boeing told me one time they had to plan around 9 month lead time for fancy connectors, even though they found them in a catalog. Helps explain why it takes so long to build planes and spacecraft!

Doesn't seem likely that was done when it was first assembled.

a few decades ago, I used to design electronics for aircraft at McDonnell Douglas, and had the same experience. When we started a new project, our first task was to get the connectors on order. Of course, these are very expensive connectors and there are a ton of options in terms of the number of pins, arrangement and type of pins, finish, etc., so they are only produced once the order is placed. The one I'm thinking of is the main connector for the black box, so it's not like a small flex strip connector. Still, it cost around $400, I think. This was for the C-17 cargo plane, and the original expected production run of the C-17 was around 400 aircraft. As such, there are few benefits from streamlining the production process, like there are for high volume products such as cars.

But... the little connector on this Wahoo looks like a relatively standard sort of item.

Steve in Peoria

well, that damage was there when I opened it up and took the foam pad off.

Most modern electronics is assembled largely without humans. Solder paste is automatically screened onto the board, and then the components are placed on the board by the appropriately named "pick and place" machine. Very cool to watch! The board then goes through the reflow machine that gradually heats up the board and melts the solder paste. It's just the final assembly of the board with the display and battery that requires some humans to be involved, and while humans can be trained to make very few mistakes, they do make mistakes.

Tests at the end of the production line catch most of the problems that might exist... some of which can be due to problems with the soldering process. There are always weird things like intermittent connections that can get through the end-of-line test and out to the customer.

Steve in Peoria

I wasn't suggesting you damaged it.

okay, I'll bite....
you don't think it happened when it was assembled, and you don't think it happened when I opened it up.
I know that the friend who sent it to me didn't open it up.
What's left?

Steve in Peoria

This wasn't mentioned earlier.

It's odd looking damage.

with it opened up, can you power it on & wiggle test the ribbons?

the battery contacts only connect with the circuit board when the two halves of the housing are in contact, so there's no way to get inside... although I suppose there might be a way to grab the battery contacts with some sort of clips. The battery contacts are fairly flush with the surrounding plastic and don't leave much to grab.

I was looking at the flex cable and connector more closely yesterday, and I think/suspect that the connector is working. I can see the upper half of the contacts move down when the latch is in the closed position.
The other end of the flex terminates on the LCD contacts, which are just a near-transparent layer of metal. No idea what bonds the flex to those contacts.
It would be interesting to see if pressing the flex harder against the LCD contacts makes a difference, but that would require that the board be powered up.
Now that I think about it... maybe I could just power the board from a power supply instead of the battery??

Steve in Peoria

dab some glue onto some peeled back copper wire that is made to create a contact for each of those connections. Be sure to make them long enough so the halves can rest without tugging at the glued temp. wires.

I'm not aware of any instances where good connections were achieved just by gluing a wire to another conductor.

Steve in Peoria

gluing work for circuit testing it would help your troubleshooting needs. gluing may be a poor choice for real world testing going down a bumpy hill... just toss it in the trash.

The latch being open as you found it means it could be busted (it looks a bit messed up). You could try just wedging the ribbon in there without using the latch.. put a small piece of plastic on the non-lead side of the ribbon (e.g. Scotch tape) and shove it in. If too loose add another small sheet of plastic. Repeat until you have a good purely friction fit, not so good that the ribbon is not going all the way in though. There could also be some junk inside the female end, might be worth trying to clean it out.

the flex does feel reasonable secure when the latch is in the down position.
I did inspect the female end of the connector yesterday(?) and it looked good. I could see the clamp mechanism work as the latch was lowered. Overall, it gave the impression of being in good condition.

I may hook up a power supply to the clips that mate with the battery and see if I can power it and poke around the flex strip and how it connects to the display and to the connector on the board. This doesn't have much prospect for ways to fix it, and I have other stuff to do, so don't be surprised if it doesn't happen. :)

Steve in Peoria

Another thought I have that might be worth a try; Try putting some dielectric grease over the connections. Might even try Gardner Bender Ox-Gard Anti-Oxidant Compound in between just the battery connections. I've used both for a garage radio repair that was having some static issues & it has been flawlessly working ever since. Beats spending $50+ replacing the radio & it took just a few minutes to open up to conduct the repair.