Eggtimer Quantum Troubleshoot

[achaskin]

Good Evening,

I wonder if anyone is familiar with this issue and could possibly chime in…

I have been testing a Quantum I recently built and am having a hard time isolating the problem I’m encountering.
When the issue is present, the quantum only beeps once shortly at power up and can’t be paired with. After most attempts to flip the power switch again, it powers right up, gives the 3 longs chirps like normal and pairs…but sometimes a gently tap or pressure on the WiFi chip is the only thing that helps. I then saw the drogue output wasn’t working so I reflowed the optoisolators as well as the WiFi chip. This fixed the drogue continuity problem but It is still temperamental at start up. (Sometimes only beeping once, then works fine when I reset the pull pin and try again) I also noticed the 4th nylon sled mounting screw next to the WiFi chip must be left out or I only get the one beep. (That’s what made me think it was the WiFi chip, as pressure and torsion have causes failure) I have checked all 16 legs on the chip and the rest of the board for poor connection and bridges but to no avail. Is there anything I may be missing or a specific part failure that would cause this? I’m stumped!

Thank you for your help,

Alexander C

 

[Voyager1]

It sounds very much like a solder joint issue with the PCB flexing causing intermittent failure. Are all your joints clean shiny solder? Are any dull or crystalline? Also, check all the visible PCB tracks for breaks.

Additionally, have you cleaned the board since soldering the components on? If you have left any residual flux from the solder between connections, then that might cause problems in some cases, particularly with sensing inputs. Some fluxes can be slightly resistive and cause problems if not cleaned off. Do you have a PCB cleaner spray or any IPA? Use an old soft tooth brush with the solvent to gently remove the flux, if necessary.

If you could post high res pics of both sides of your board, that might help folks here to isolate your problem.

 

[cerving]

If you're using the solder that we provide, you should ONLY use a no-clean flux such as Kester 951, and do NOT clean off what little flux residue will be remaining. You'll do more harm than good.

Chances are that you have a cold solder joint and it's going intermittent when you "move" things (which you should not do). As Voyager1 mentioned, all of the joints should be shiny and not blobby... if they don't look like the joints in the assembly pictures then you're not doing it right.

 

[rharshberger]

Good Evening,

I wonder if anyone is familiar with this issue and could possibly chime in…

I have been testing a Quantum I recently built and am having a hard time isolating the problem I’m encountering.
When the issue is present, the quantum only beeps once shortly at power up and can’t be paired with. After most attempts to flip the power switch again, it powers right up, gives the 3 longs chirps like normal and pairs…but sometimes a gently tap or pressure on the WiFi chip is the only thing that helps. I then saw the drogue output wasn’t working so I reflowed the optoisolators as well as the WiFi chip. This fixed the drogue continuity problem but It is still temperamental at start up. (Sometimes only beeping once, then works fine when I reset the pull pin and try again) I also noticed the 4th nylon sled mounting screw next to the WiFi chip must be left out or I only get the one beep. (That’s what made me think it was the WiFi chip, as pressure and torsion have causes failure) I have checked all 16 legs on the chip and the rest of the board for poor connection and bridges but to no avail. Is there anything I may be missing or a specific part failure that would cause this? I’m stumped!

Thank you for your help,

Alexander C

If your cellphone has a good camera (most do) photo all 4 side views and top and bottom angles from as close as possible to get nice clear pictures then post to this thread, one of us or Cris (most likely) might spot the problem.

 

[achaskin]

Thank you for the responses. So I addressed the flexing problem… the sled was actually slightly warping from the pressure of being secured down. I added spines on the sled for rigidity and since have only gotten the quantum to fail with one beep once. It took a tap on the WiFi chip to make it work again so I know the issue is one of its leads.
Upon inspecting those again to take some pictures, I realized that a couple of the joints aren’t picture worthy so I’ll rework those again.
I will get back to y’all with pics of the solder connections if the problem persists after that… I just want to make sure my solder work will stand up to the G’s of flight.

 

[cerving]

Are you using spacers between the sled and the Quantum? There are parts on the bottom of the board, if you don't have spacers and screw it down, you will almost certainly mess up the solder joints on the optoisolators, and possibly break the leads where they meet the body.

 

[Voyager1]

Out of curiosity, what video camera setup are you using there in your 1st image above?

 

[achaskin]

Are you using spacers between the sled and the Quantum? There are parts on the bottom of the board, if you don't have spacers and screw it down, you will almost certainly mess up the solder joints on the optoisolators, and possibly break the leads where they meet the body.

Yes, there are nylon stand offs that keep the board well above the sled. The 4th nylon screw is left out next to the WiFi chip because the head is too large in diameter and overlaps the chip. I think that and the flexing of the sled contributed most to the problem. I will also rework the leads on the chip tomorrow evening just to be sure and run some more ground test. I anticipate a couple flight without relying on the computer for main recovery events just to make sure it’s running and reading throughout the flight.

 

[achaskin]

Out of curiosity, what video camera setup are you using there in your 1st image above?

That is a Run Cam Split 3 Lite. It doesn’t have the traditional housing like the rest of the FPV cams so it requires some fabrication of a mount. (I also don’t have a switch band as this bay is installed in a coupler.) This bay is all for preliminary testing but the main L2 project will use a few of these mounted in a switch band to obtain a complete fin to nose cone view. These little guys will also be perfect for internal data collecting cameras on big airframes!