I could do with a bit more info regarding the parts though like the capacitors. Does it matter what ohms value they are, and some have different % values, again does this matter what this value is?
If you mean ESR resistance, don't bother. Same goes for the tolerance. I used the cheapest tantalum caps I could find, either from Mouser or off eBay and they work fine. As for the operating voltage, rule of thumb is at least twice the power supply voltage. 16V will suffice in most cases, but I'd pick 25V to be extra safe.
Since the values of ceramic caps C75 (7.5pF) and C79 (20pF) are uncommon, i.e. not in the regular E12 range, I would take those slightly more seriously. You could end up with your RTC and/or the flicker fixer being off.
Leave out R31 if the battery is not rechargable. My lithium battery (Saft LS14250) was getting disturbingly warm when powered on.
In case you are wondering about the components marked as "n.b." or otherwise without a value, leave them out. I think "n.b." means "nicht bestückt" (as in "not mounted").
50MHz clock oscillator IC61 can be replaced by 100MHz. In that case IC78 is needed, resistor R122 must be omitted and R135 mounted instead. IC78 acts as a divider by two, providing a 50MHz clock with a guaranteed 50% duty cycle (which is essential).
Directly solder IC27 to the board. It is a high frequency PLL and a socket could affect its operation.
For testing, don't install the 8MB fastram or the 1MB flash just yet. The board should work with only the 2 megs chipram installed (IC7..10), but it will run crippled at 7.1MHz.
The 3 RCA connectors shouldn't be mounted tight to the board but slightly (1-1.5mm) raised for the rear panel of an A1000 to fit nicely. Also, if present, don't solder the prongs from the sub-D connectors to the mounting holes but remove them altogether if you want your board to properly fit into an A1000 case. It has threaded standoffs for every connector.
Notice the RJ9 keyboard connector being upside down compared to the ones on eBay etc.. You need a Molex 95001-7441. The plugs on the original A1000 keyboard cable are also reversed, so beware if you are making your own.
So much for now. I will post more if anything else comes to mind. The GBA1000 is an awesome kit and pure eyecandy when fitted into an A1000 case. Good luck!
