User manual

Construction
Apart from the connectors and switches the entire design uses surface mount components. This was
done in order to give a professional look, and reduce cost and size by using a standard UB5 Jiffy box.
The PCB is used as a replacement for the jiffy box front panel and this provides a very elegant and
durable appearance.
The PCB used in the prototype is a double sided board mainly for the purpose of improving the red
solder mask finish. The shield plane on the top layer is connected to VGND.
All components are relatively large 0805, SO and SOT packages so soldering is pretty easy using a
basic iron. See the March 2008 issue of Silicon Chip for an article on how to solder surface mount
components if you are new to this.
There are a few things that make SMD hand soldering much easier. A small chisel point tip (not
conical), fine multi-core solder (0.56mm or better), and a pair of fine pointed tweezers. If you have
these things then hand soldering is a cinch.
Start with the three IC packages, making sure of correct polarity on U1. Follow with the passive
resistors and capacitors, taking extra care with the precision resistors not to damage them with
excess heat.
Applying a small amount of solder to one pad first makes it easy to “reflow” the component into place
while you solder the other end.
Next solder on the LED. This is a special “bottom emitter” LED which is effectively soldered in upside
down, with the light coming through a cutout in the board. Be sure to match the polarity to the
silkscreen.
Next solder the battery holder into place ensuring the correct polarity. Apply the iron and then solder
to the top side of the flat pin instead of the pad for this part. The solder should then reflow easily to
the pad underneath.
Turn the board over and install the two slide switches ensuring correct orientation. If you have the
vertical switches then the side with the metal indent should face to the outside edge of the board.
Side mount switches should have the switch lever towards the middle of the board. Ensure the
switches are flush with the board and aligned straight. Tack one pin down first to check before
soldering the rest.
Finally the banana connectors. Unscrew them completely first, removing all nuts, washers and solder
tags. Install them on the top side with just the plastic spacers touching the top side of the PCB. Next
put the solder tag on the bottom side and solder it only to the smaller adjacent solder pad. Then place
the washer and screws on top and tighten. Feel free to add a thread-locker and/or glue if desired.