Dead Rosetta - SD card slot has come adrift - Updated

[grahambaker]

Some time ago I had some reliability issues with my 'powered by a Charge2' Rosetta, but these went away if I followed the mantra of pulling the USB port circuit breaker before engine shutdown, and not powering it up until after engine start. I was never really convinced that this really got to the bottom of the problem, but it's seemed to work for the last few months.

Out of the blue today the Rosetta just wouldn't work. USB or Anker battery, nada. All I'd get was three green flashes from the Bridge board, and a solid red light from the Pi, and nothing more. On the bench back at home I've found the problem, in that the outboard end of the SD card socket has come away from the Pi, leaving it hinged from the inboard end, so the poor bugger can't boot up and just sits there. I suspect a flakey SD socket connection has been the problem the whole while, and it's finally given up the ghost.

My soldering skills certainly aren't up to the job of reseating/replacing the SD card slot, so I'd welcome suggestions on options.

- can anyone replace the SD slot for me?
- has anyone a dead rosetta with a good Pi they'd sell me?
- is the right Pi still available to buy new?
- do PAW Towers offer a sensible trade in against an Fx?
- any other suggestions?

As an aside, I had to fly with a SkyEcho@ today in its place. My aircraft is certified ADSB out equippped so I was only using it in receive mode. Whilst it saw plenty of traffic, I remain convinced it's highly selective in what it does receive, as I flew above, behind, below and in front of a mate in another certified ADSB out equipped aircraft for two hours and it never saw him once, despite Vector showing his aircraft broadcasting loud and clear. I just can't bring myself to trust the SE2 the way I do the PAW.

[JCurtis]

The power up sequence will be because cranking the engine will cause a low voltage. This may cause the Charge2 to switch off, so reboot the Pi.

That looks recoverable, possibly. If you can’t get a replacement Pi easily happy to have a look at it.

[grahambaker]

I've just seen that a new Pi 3B+ is about £40.

Can one of the tech team confirm yhat this will work OK? If so I may just short cut the process and buy a new one now.

[exfirepro]

Hi Graham,

Thanks for posting - that's certainly a new one on me. I have come across a few dodgy microUSB sockets (including one of my own, which Jeremy kindly replaced for me), but have never come across a microSD slot casing become detached before.

The obvious cause would be downwards pressure (away from the printed circuit board) applied to the socket, such as if, for example, the Rosetta case was disassembled without first removing the microSD card - but that usually breaks the end off the card, not the socket. To force the socket off the board would require considerable leverage - unless of course the solder joints were already weak.

As the actual contacts are all on the PCB itself, it should just be a case of re-soldering the two front case mounts back onto the PCB - unless the force has lifted the solder tracks off the board. in which case there wil be nothing to solder to.

A replacement Raspberry Pi3B (not Pi3 B+ *) if you can find one, is the obvious fix, or a resolder if the tracks on the board are still intact. I have just swapped a Classic for a customer to an unused Pi3B which he got from eBay, so they can still be found. If you swap the Pi, remember to advise Ash (support@pilotaware.com) of the new MAC address and he will issue a new licence code for any remaining licence period.

* I run a Pi3B+ on one of my 'test' units. It will work, (though not officially supported) and draws a a fair bit more current than the 3B in use (though still well within the capability of your Charge2.

Please let us know how you get on.

Oh and OK on your comments re SE2.

Best Regards

Peter

[JCurtis]

There is loads of stock of the 3B+ in the uk, Rapid electronics have 200+.
Definitely the easiest solution.

I thought they had ceased production of the 3B with the + version the direct replacement.

[grahambaker]

Thanks both - I've managed to find a brand new boxed 3B on eBay at not much more than half the price of a new 3B+. Perhaps better to stick with the devil I know, and lowers the possibility of power issues if I have to take it to another aircraft and run off a battery.

I'll contact Ashley once it arrives.

Once it's all working OK would the old one be of any use to PAW HQ for repair/cannibalising for ATOMs? I'll send it to you if so.

[exfirepro]

Hi again Graham,

I have PM'd you.

Peter

[grahambaker]

Just to bring this to a close - the Pi transplant worked like new on Friday when I finally had the chance to test it in the air

Side benefit - all the USB ports, and more importantly the power socket, are nice and snug on their respective plugs.

[exfirepro]

Follow-up For Information

I asked Graham to send me the old board so I could examine it - never having come across this fault before. I have it sitting here in front of me as I type - thanks Graham.

The following is simply a statement of what I found and should not be taken as implying any negligence or inappropriate action by Graham - simply a cautionary tale for us all. It could easily have happened by the projecting end of the microSD card catching on something at any time when the unit was being fitted or removed from the plane, or from any bag it might have been carried in.

You should be able to see from Graham's earlier photo that the card slot comprises a thin stainless steel 'cover' into which is clipped a plastic 'inner', which forms the card mount itself and contains the contacts to link the card to the board. The two parts are held together during construction by very small moulded clips at each corner of the plastic liner. The card slot also contains a fine 'reed microswitch' inside the right-hand side at the back - which closes when a card is installed, telling the board that a card is present. The whole unit (including the 4 case mounting points, 8 separate card contact fingers and the 2 switch contacts) is then surface mounted onto the PCB during manufacture as a single unit.

Unfortunately, this one looks like it must have experienced downwards pressure being applied to the projecting card end at some point, which has dislodged the stainless steel cover from the plastic clips and broken the casing away from the PCB, though the printed circuit board itself looks intact (i.e. the damage hasn't pulled the tracks off the board). The reed switch has, however, become twisted and distorted (probably simply by trying to reinsert a card after the case had unknowingly sprung apart). Unfortunately this means that the only practical 'repair' will be to remove and replace the 'card slot' as a unit.

As an exercise, I have now obtained a replacement card slot and tracked down a friend with the necessary temperature controlled heat-gun equipped solder station to carry out the repair. Now I just need to find the time to give it a go.

Best Regards

Peter

[JCurtis]

Good luck, Peter!

The Pi is (at least) a 6-layer PCB, so you may need to pre-heat it a little to make life easier.  You will need a good flux when removing the cardholder and gentle lifting until it becomes free.  Clean the pads to get them as smooth as possible. Flux and solder wick are all you need.

Any lead-free solder paste should be OK for the replacement.  Personally, I use a SAC305 paste for manual assembly work, specifically SK P2-5 SAC306 88.5 20-30 T4 from SolderKing, made in the UK :-).

Out of interest, do they still use Molex 1040310811 cardholders?