What is a blank PCB?

    A blank pcb is the main board minus all chips and components.

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.



During the soldering work, I'm afraid of getting stuck in case of errors. Any ideas?

    Gleaming from the discussion above:
   In short, build the main board first. Add the RAM, flicker fixer and IDE controller when you've tested that the main board works.

I'm afraid to dammage parts during the soldering. Any suggestions?

Here's another soldering tip…

    When assembling the board solder the FlashROM as the very last thing. The reason is that the space between the pins is very short there and it is therefore the easy place to make a solder bridge. Thus if you test the board prior to soldering the FlashROM and the board works, and then it doesn't work after the FlashROM is soldered, you made your error finding much easier.

What are the board's parameters?

    4 Layer (35µm , 35µm , 35µm , 35µm)
    1x Materials (FR4 0,71 35/35)
    4x Prepreg (7628,7628,7628,7628)
    Thickness: 1.54mm
    Panel size: 344.488mm x 314.007mm

    4648 Drills. / Panel.
    21 Drill changes
    Smallest drill Ø: 0.3mm
    Technology: >= 150µm
    SMD: doppelseitig >= 1/50"
    Finish: chem. Ni/Au
    Soldermask: on both sides
    Identprints: 1
    Peel off mask: no
    Mech. working: Fräsen;
    E-Test: Yes

What size and case does this motherboard fit in?

    The board fits in a  standard Amiga 1000 case as shown below. Picture courtesy of a1k.org.

How fast is the GB A1000 compared to classic Amiga computers, such as the A1000?

    Here is SysInfo information and benchmarks. These picture shots were taken from a working GB A1000, courtesy of a1k.org. Overall, the GB A1000 is much faster than a A600, with a CPU/Mhz of 51.8Mhz. For more information about Sysinfo, see SysInfo doc file.






Does this new motherboard have the capability to connect to modern monitors?

    The design includes a "Flicker Fixer".

Will this computer have a hard drive?

    The design includes a HD controller.

Can I substitue parts?

    According to Georg you can use a modern substitute for the FiFo RAM in the 2320 AGA ScanDoubler but the modern FiFo RAM is not pin compatible with the GB A1000 board, therefore it is not usable "out of the box".

How critical is the selection of 74-logic?

    In other words, When it says 74LS, must it really be a LS or could it be replaced with an HC/HCT? The 74F, could it be replaced with AC/ACT?

    For some logic chips it is important to use the exact chip described but in some places alternative chips can be used. Each of the mentioned chips have different properties with regards to power consumption, switching speed, driver performance etc.

    A few examples: For the 74F245 I also tried the LS and ACT varieties and it worked with all three types even though the LS is a tick too slow and the ACT overshoots the bus signals due to it's higher switching speed.HC and HCT chips are not suitable in this place and the use of a F-type chip will result in a reduction of operational safety which in turn can lead to instable operation of the board. - Georg Braun



What color is this motherboard?

    The bare boards ordered for the group are blue!

What are some of the features of this system?

What are the correct cycle times for the MSM514221 memory chips?

According to Georg, the MSM514221-30 and MSM514221-40 have been tested. They both work. The MSM514221-60 have not been tested and Georg doubts they would work.