Hey all, here's some pretty general info on the board designators or anyone needing a decent shot of a bit of the motherboard to trace out something for repair purposes or whatever, so here ya go. There are NO component values in here, just how the board can be looked at quickly and "read" to tell what type of part you're dealing with and where it's located, also so you can find a part quicker to get a measurement or remove it without having to scan over the whole board and possibly waste a good bit of time looking for some tiny, tiny part.
The board is setup into grids...
The first 1 or 2 characters of the board designation (the little white lettering close to the part, it's either 4 or 5 characters long) are the parts type...
C - Capacitor
D - Diode
FB - Ferrite Bead (Inductor)
Q - Transistor
R - Resistor
RT - Thermal Resistor
U - IC
GND - Ground
DB, FT and TP are for testing purposes, some go thru the board and others don't, they're for taking measurements at different locations in the circuits on the board and all from the bottom of the board, like in a "bed of nails" setup. Ya can think of that like a board with 100 pins sticking up from it all in different places, then the board sits in it and each of these DB, FT and/or TP points touches one to take the reading from it. Kinda like having 100 arms and test leads from multimeters, O-scopes or whatever all connected to the board at the same time, but a computer generally does that side of it.
The second 2 are the grid the part is in, then finally the last one is the number of how many of that type of part are in that grid. It doesn't mean they're all the same, just how many there are of that type of part in that grid.
So to recap, the board designation doesn't give ya the value of the part, but it does tell ya the type of part it is, where it's at in the grid and how many of that type of part there is in said grid. Like R2R3
is a R
esistor in grid 2R
and it's the 3
rd Resistor in that grid.GRID9M
--- --- --- --- --- 3M 2M 1M9N 8N 7N 6N 5N 4N 3N 2N 1N9P 8P 7P 6P 5P 4P 3P 2P 1P9R 8R 7R 6R 5R 4R 3R 2R 1R9T 8T 7T 6T 5T 4T 3T 2T 1T9U 8U 7U 6U 5U 4U 3U 2U 1U9V 8V 7V 6V 5V 4V 3V 2V 1V
This is ONLY for the bottom of the board and is NOT the Elite motherboard. The top of the motherboard is setup the same way, but labeled A, B, C, D, E, F, G, instead of the M, N, P, R, T, U, V the bottom uses. The letters O, Q and S aren't used since they're similar to 0 and 5 and that can get confusing right quick.
There are 2 versions of the "standard" 360 board that I know of, one with the ICS chip for the Ethernet, the other has a much smaller BCM chip. Depending on which chip is in your 360 there will be some slight differences on where some Resistors and Capacitors are located around that chip. For example, the ICS chip has a Resistor at R1M3, while the board with the BCM chip does not, this is normal. Likewise the board with the BCM chip has parts the ICS one does not, the differences are on the top and bottom of the board around this IC (possibly elsewhere also), so make sure ya know which one ya have before you go thinking a part is missing or that ya have a component where it isn't compared to these pics, this is a board with the BCM chip. The boards are technically the same, they're setup to accept either IC, the reason I say there are 2 versions is because if you were to go component checking around this area you basically have 2 different setups, so it's easier to keep them seperated by versions, ICS and BCM. I may go thru and document all the differences one day, but I'm sure ya can imagine that's about as much fun as pulling out your own teeth with a spoon and no anesthesia.