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Tips for the difficult components:
Microcontroller: Apply lots of solder to the pads without worrying about solder bridges. Remove the solder bridges with solder wick.
Crystal: Apply a lot of solder on the 4 pads, enough solder to make half a sphere. Place the crystal on top of the solder, and hold in place applying downward pressure. Then apply heat to the solder and it will flow up to the crystal.Micro USB Connector: Apply solder on the 5 inner PCB pads. Place the connector and carefully align the pins with the pads. Once in place, solder one of the thru hole pins. If the pins are still aligned, then solder the remaining thru hole pads. Then with a fine soldering tip, apply heat to the 5 inner pads. Bridges can be removed with solder wick.
Display: Apply solder on the PCB pads first. Place the display, inserting a paperclip in the alignment holes will help keep the display in place. Apply a little more solder on the connector (don’t worry about creating solder bridges), move the tip of the soldering iron as if you were painting in between the connectors, with an outward motion. Then use the solder wick to remove excess solder.
After completing the SMT assembly, install the remainiing parts:
Tin the OLED pads on the PCB.
USB micro connector:
Tin the 5 micro USB signal pads. Insert the connector and verify aligment, then solder the support pins. Use the iron tip to solder the signal pads to the connector. When the connection is good, you will see the micro USB pins turn shiny, apply more solder if necessary.
Double side tape:
Place the tape in the designated area.
Place the headers, make sure that the headers are vertically aligned. I used some old boards that I glued together for this purpose but using a breadboard will also work.
The 1x2 headers need to be cut on the top of the board. This is needed to make space for the tactile switches. Be careful not to cut any traces on the board while cutting the headers.
Solder the headers. Try not to make the joint for the 1x2 headers too tall.
Place the tactile switches. Make sure the tactile switches are pushed all the way down and are seated correctly. If a tactile switch does not seat correctly, double check that the solder joint beneath is not too tall.
Solder the tactile switches. Some of the pads are connected to the ground plane, they will require some extra heat.
|Check your board for solder bridges, check that the headers are vertically aligned.|
|Before removing the peeling from the tape and folding the OLED, power up the board to verify that it is working. Check that the OLED is working and that the -5V and 3.3V are present.|
Finally, after verifying that everything works ok, peel the tape and fold the OLED in place. Remember to enter the factory options (keep pressed the MENU key during the splash screen) and perform the offset calibration.
Optionally, you can install a 2x3 header if you want to be able to connect to the microcontroller with the PDI interface.
And if the device doesn't work, check the