Following traces

[bustinthejustin]

Hey any tips on how to follow traces such as those in 360 controllers, ps3 controllers, etc.? Cause they royally confuse me O_O

[802Chives]

most digital multi-meters have a continuity checker built in to them. so that is what you would use to check traces by measuring whether they have continuity from a known point to an unknown point. You will want some fairly sharp probes as often you will be checking very small pins on the boards.

You can also build a continuity checker with an LED and or a Buzzer.  Google it, it is often a first soldering project that people do when getting into electronix as it is a very helpful tool.

Most of the time on these controllers, someone has already done what you want.  I know Xbox Scene has a lot of hi-res documentation of controllers, and some aready have the important traces highlighted.

[bustinthejustin]

Alright thanks a lot If I were to just follow traces, you have any hints for that? Because traces usually end in via holes and that confuses me lol :S

[802Chives]

following traces by eye is a good method, howeve not always going to work. In say an xbox 360 controller board it works fine as there are only a top and a bottom layer where the copper makes paths.  However printed circuit boards can have as many as 16 layers in them so that method wont always work if the path is on a buried layer.  Commonly people use a 4 layer boards where the two inside layers are ground and power, and the signals are routed on the outside layers.

Visual inspection works, but a continuity checker will still help to confirm that you did your tracing right.  A good method for visual tracing is to take some high-res photos of the board in question, and then use a graphix program to highlight the traces with different colors on both sides of the board.  If you see a trace go into a via and doesnt come out on the other side, you know you have a buried signal layer, in which case some probing with a continuity checker will be the only way to find out where it pops up again.

Oh and a bit on via holes: vias are a way board designers use to transfer the signal from one layer of the board to another.  they are are the holes that are plated on the inside after drilling in order to allow a path for electricity to travel from one layer of a board to the next. 
EDIT: As the wise Alien has kindly pointed out, there are two kinds of vias, both a through hole via that goes the entire thickness of the board, as well as a blind via that only goes as deep as the layer it is trying to make a connection on.

For anyone who makes their own boards, vias can be easily made by making a through hole with pads on both sides and sodering a wire between the two pads on either side of the board to make the connection.

[SN!P3R]

good info chad XD

[Alien_X]

Even if the trace isnt going all the way from the top of the board to the bottom, a via will still be present that will be through the whole thickness of the board.

Sorry Chad but I am going to have to dispute the above point, unless I misunderstood it entirely!
Have you heard of the term a blind via?
On the PSP 1000's (And several other systems) motherboard there isn't a single via which appears on both the top and bottom layers - all of them are blind, which makes it insanely hard to trace the path to the signals and where they are processed (Mips).

Also, another method to connect a top and bottom signal layer together is to use a 0 ohm resistor and pads on either side, although this is slightly more cumbersome!

[802Chives]

damn, i guess you are right  blind via does ring a bell, I guess I need to look into modding one of these psp things you all are talking about

good luck tracing blind vias.

[bustinthejustin]

On the sixaxis board, there are commonly holes at the end of traces. I assume these are vias, but are they really that small? I can't even fit a piece of magnet wire through so I can trace it on the other side >.<