How can I repair Featherweight GPS Tracker after hard landing?

[jahall4]

"I had a similar problem. Emailed Adrian (owner of Featherweight) multiple times. His only response was to ask for pictures.
Finally sent the tracker to him to see if he could fix.
He totally blew me off!
This was 3 months ago."

I doubt that Adrian "builds these" himself and trying to rework an SMT board is a bear without specialized equipment. Plus your board itself might be dorked with a broken contact trace in the board also. Replace the module and it still might not work. I consider it a waste of time to try to salvage. Just move on.
Rocketry is like fishing. If you want to catch fish, you're going to lose lures on snags. You fly rockets and you're going to have CATOs and deployment failures eventually. Whacked electronics are part of the game.
I had a deployment altimeter I just bought and immediately ground tested it. I do this with every new component now. It had a glitch in one of the deployment channels. I phoned the maker, told him the testing procedure I used and that the unit was not flown. I sent it back and he fixed it and told me what component was defective.
That's the only time I'd explore fixing a board. Anything that has been subjected to severe forces that shears parts off the board can have unseen board defects and can be a crap shoot to fix.
I had an altimeter that was dorked in a hard landing. Replaced a capacitor and it ground tested fine blowing ematches in testing mode. I am a paranoid person about electronics so I used it as a backup deployment altimeter. Good thing I did as the primary controller fired the charges nominally. When I got the rocket back, the "fixed" deployment altimeter didn't blow any of the charges. Ground tested again and the charges blew. There was a "gremlin' in there I likely wasn't going to find. That device ended up on the junk pile. If I had flown the supposedly "fixed" altimeter by itself, it would have been a lawn dart. YMMV but I don't fly salvaged electronics from lawn darted rockets. Kurt Savegnago

It has been Just the opposite experience with Jim at Missile Works. By accident shorted across a trace and popped it. He helped me jump wire around it.

 

[Chad]

I only wish that the audio tracking part of the iPhone app provided some of the features of the more expensive Multitronix “Kate” — like maximum velocity, alt-az and distance callouts on descent, and landing detection.

@adrian open source the blue tooth comms you’re using for the tracker. Then the community can produce different mobile apps (including android versions) with your existing app as the official supported one. It wouldn’t cost you anything except the time to write the specs and then you gain sales because your tracker hardware is one of the few out there that software guys can build against.

 

[ksaves2]

I have 30 years of experience with SMT, and I can fix one of those with a regular iron. Everyone else, probably not, lol.

To fix anything like that, you need at least a thermocouple based temperature sensor, solder paste in a syringe, a heat gun, some desoldering braid,. (not a blowdryer, they won't go hot enough. Clean off all the old solder with a regular iron, by adding a bit of clean solder. and remove it all with the braid, so you have a clean silvery surface on both parts.
Then you put a tiny dot of solder on the pads, put the part in place, and gently heat the solder to about 350-400 degrees, just enough to melt the solder paste. Too much heat will kill the part. If you look up the chip's datasheet, it lists the maximum solder temp and duration. If you're going too long, stop, let it cool to room temp, and try again.
Wear an antistatic wristband while handling un-packaged electronic boards.
You have about 5 seconds at temperature to make the connections.
I stick things like that to the antistatic mat with double sided tape.
A stereo microscope and a good set of tweezers are also nice to have.

Quick question. How do you get the old GPS "base" off the pads first without damaging the traces to put a new one on?
Sure, anyone can solder a new one in but with just a low wattage soldering iron, how do you get the old base off the board? Inquiring minds want to know? Kurt

 

[SDramstad]

Quick question. How do you get the old GPS "base" off the pads first without damaging the traces to put a new one on?
Sure, anyone can solder a new one in but with just a low wattage soldering iron, how do you get the old base off the board? Inquiring minds want to know? Kurt

Long pair of tweezers and a blow torch.

 

[ksaves2]

Long pair of tweezers and a blow torch.

You need a question mark instead of a period at the end but that is an absolutely hilarious reply! You got me going there for a minute mine you! Great laugh for me. Can't get the GPS base off? Might as well toast the danged board!!! Kurt

 

[SDramstad]

If you sweep the flame across at the right speed it actually works.

 

[Adrian A]

@adrian open source the blue tooth comms you’re using for the tracker. Then the community can produce different mobile apps (including android versions) with your existing app as the official supported one. It wouldn’t cost you anything except the time to write the specs and then you gain sales because your tracker hardware is one of the few out there that software guys can build against.

I'm paying (quite a bit) to get a Bluetooth app developed for both Android and iOS for the Blue Raven, and I'm planning to extend it to the GPS trackers as well once the Blue Raven is working, which will replace the existing Featherweight GPS app. I'll think about publishing the Bluetooth interface, since I agree I don't see much downside if someone wants to roll their own. I would only support over-the-air firmware upgrades via the Featherweight app, though.

 

[ksaves2]

If you sweep the flame across at the right speed it actually works.

Sheeeeoooot, I'll keep that in mind and try it if it happens to me. What the hay, got nothing to lose. I have some small handheld hobby torches that would be perfect to try. Main thing is if I have a lawn dart, the electronics are shattered besides having the GPS tracker board pulverized.
I did have an early Eggfinder GPS tracker that I "just" built and working. Wasn't but 30 minutes old and fell off the windowsill! I "just about had a heart attack." It was one of the first ones that came out and I was porting the output to a live mapping program for a test. Half the GPS antenna cracked off and I managed to get the base off the board and tossed it into the junk drawer for several years.
I messed with GPS for a time and looked at components. Found some amplified bifilar GPS units and I should'a bought several of them. They were dynamite.
Well I acquired some of these GPS units. managed to get the base off the Eggfinder and Chris was kind enough to tell me what I had to attach to what. It was a 5 volt unit and they are getting hard to find.
Oh wait, here's a picture. I had a unit sitting on top of the freezer.

 

[Chad]

I'm paying (quite a bit) to get a Bluetooth app developed for both Android and iOS for the Blue Raven, and I'm planning to extend it to the GPS trackers as well once the Blue Raven is working, which will replace the existing Featherweight GPS app. I'll think about publishing the Bluetooth interface, since I agree I don't see much downside if someone wants to roll their own. I would only support over-the-air firmware upgrades via the Featherweight app, though.

i regret i have but one like to give. I'm really excited about Blue Raven!