Here is some information from www.gba1000.info before the site disappeared (copied and/or paraphrased for the sake of clarity).

In what order should I proceed to populate the board?

Some of the members are currently discussing best approaches. Here are some ideas:

Schneemann: I am not afraid to solder the board, but I’m worrying getting stuck in case of any error. It will be not my first PCB, but the first of that size and complexity. I hope that it will be possible to set up the board step by step, as far as Georg just “easily” integrated the IDE-controller and the flicker fixer via (not directly visible) standard Amiga-interfaces. That means the main-part should work even without flicker fixer and IDE-controller. If I’m right, most of the GALs belong to these optional parts. The CPU, FPU and custom chips are socketed (easy to check). More difficult is the RAM (hard to solder and getting damaged fast), but if this part works, we should see a picture, e.g. with an external flicker fixer, on the screen, then the rest could follow.

Kristian95: You are right there are many possibilities for errors and trouble shooting will most likely take most of use as much time as the actual soldering. The Flicker fixer is indeed optional (no changes necessary to the build if you leave it out). Also the IDE controller is optional, I can’t remember what change you need to make to the build, but it is documented in my translation of the user’s guide. I don’t think it should be a big problem getting the GALs programmed. Do you know whether it would be “easy” to make the RAM socketed instead of surface mounted? If it is we might consider doing so 🙂 Therefore we should find such kind of build-phases in order to have chance of any testing.

Schneemann: The GALs are not the problem. It is in general better to have parts of the board tested and running well before starting with other parts and unfortunately, you can’t test the IDE controller and the flicker fixer (that’s where the GALs are used) without the CPU and RAM working. So I suggest the best build order is vice versa, i.e. leave most of the GALs as well as SD and IDE for later and start by building and testing the bare computer.

 

This discussion basically boils down to:

• Leave building the IDE Controller and Flicker Fixer sections for later (they work independently of the main logic)
• Build the main part of the board and get it to output a video signal using an add-on flicker fixer like one from Indivision.
• The main part includes the Amiga custom chips, CPU, fpu
• After you have a video signal, you can solder the RAM and the Flash ROM (it’s a good idea check for video signal after you solder each RAM chip and after the Flash ROM.) The RAM and the Flash ROM have a lot of pins and they are very close together and this introduces the possibility of making many soldering mistakes. Checking after each chip allows you to make sure you did that one properly.
• The challenging GAL chips seem to be part of the optional flicker fixer and IDE controller sections and can be tackled last.