Originally posted by N Waring:
I've not got that much experience of electrics / soldering and wanted to ask whether it is obvious which way round the components need to be soldered onto the board? e.g. I know diodes need to be the right way round - I assume it's straight forward to work out.
It is pretty easy, most things are marked which way they go. In retrospect I wish I would have done a step-by-step making my V3.2 board, that probably would have been useful. I'd do it like this, in this order (all directions refer to having the board component-side up, with the LCD connector closest to you):
<UL TYPE=SQUARE>
<LI> Resistors - Doesn't matter which direction they face. I'd solder all these in first, because it is easy to insert them then flip the board and let it rest on the resistors, which will hold them in place while soldering.
<LI> Router connector / 12V power pin header - Lord help you if you put these in the wrong way. It is easiest to do these now while you can still lay the board flat. Don't do the 12V barrel jack connector now!
<LI> Ceramic Capacitors - Again, no polarity on these. They're the small 0.01uF and 0.1uF capacitors. Do all these next.
<LI> Potentiometer - This only goes in one way.
<LI> Reset button - I'm betting you can try really hard and get this jammed in the wrong way but don't do that!
<LI> Shift Register / ATmega DIP socket - these both have notches on them to indicate the correct direction they go. On the V3.2 boards, they both have the notch on the left. When I do these, I usually do two diagonally opposite pins first, then pick up the board and hold my finger against the component then re-heat the soldered pins. This takes up any slack. Then solder the remaining pins.
<LI> Diodes - these have a stripe on them that matches the stripe on the PCB. Two of them lie flat but D1 by the BLW connector you'll have to bend so it is sticking out of the board.
<LI> Backlight transistor Q2 - Align the flat edge to match the PCB screen print.
<LI> LED - This one is confusing because the screen print is messed up. The shorter leg of the LED (this is the 'cathode' or negative side) goes in the hole closest to the LED1 printing (closest to you)
<LI> Electrolytic capacitors - all these have their negative side labeled on the component, and the positive side is labeled on the PCB. Bonus: All the positive holes are on the left, all negatives on the right. If I remember correctly, C8 above the DIP slot is shorter so do that one first then all the others.
<LI> LM7805 / MOSFET - The heatsinks on these align with the white bar printed on the PCB. Look carefully at
the picasa picture here and note you don't want to insert them fully into the holes. Bend the legs down 90 degrees where they get thinner then insert them into the holes and let them sit on top of the components you've already soldered. Then flip the board and solder them in place. With them bent like this they take a lot less space in the case.
<LI> Resonator - this has no polarity
<LI> Remaining pin headers - With these I solder one pin with them at whatever angle they want to be, then pick up the board and hold my finger on them and heat the solder joint until it flows again and make them as straight as I can. Remove the soldering iron and let the joint cool before you burn the crap out of your finger. Finally, solder the remaining pins.
The PROBE connector, you'll want that angled a bit (inward probably) because the WRT54GL case jams up against the connector on final assembly. Having it angled makes it slightly less tight.
The FTDI connector (if you use it) you probably want a
slightly angled outward to allow the cable just a little clearance from the RESET button.
[/list]
I think that's it?
