MMA7455L soldering explained
Ian asked me to solder some MMA7455L on the USB POV Toy boards. So when I got them the first thing i did was clean them all with some acetone. After that I pre tinning the pad s of the chip so it had some solder with flux on them.
I did the same thing on the boars and used solder wick to get the solder of but leaving a layer of flux.
Then i placed the chip on the board (no extra flux used, all the flux was from the solder) together with 2 bits of solder so i got an indication of the board temperature.
I used 2 extra boards so only the board i’m reflowing heats up and not the thick A4 sized FR4 board I use as a soldering surface.
After cleaning the flux of with some acetone and cotton swabs
Testing the communication to the chip with my Bus Pirate v4 and using some tape to keep the cable in place because the connector isn’t soldered but kept in the board by bending the pins so there is no need to unsolder it when I’m done
When testing the last board i measured a short between the chip-select and ground
So with the chip removed i charged 4 18000uF capacitors to 15V and pressed the probes to test connector.
After connecting the other end of the test lead to the caps the short just blow away with a nice flash and a little bit of smoke
And with all the boards soldered and tested it was time to ship the back to Ian
He let me keep the board that had the sort in it, when putting some more parts on it I found some more shorts but those had to go with a scalpel.