PCB Layout

A project log for Recreating the Jupiter Ace

Recreation of the 'Fastest computer in the Universe' that runs FORTH.

Cees MeijerCees Meijer 06/15/2019 at 12:475 Comments
OMG ! How am I ever going to solve this ?

After finishing the schematic, it's time to start the PCB layout. First this requires some decisions on what component shapes to use. All the ICs are easy, these are just standard DIP packages. The capacitors are all ceramic discs, but with a 5mm pitch, where 2.54 is more common these days. Resistors are all good, old-fashioned standards 0.25 W radials with a 10 mm pitch.

For the 3.5 mm jacks that connect the power and the tape recorder I chose a model that's available at  almost every electronics shop. (Sparkfun sells it as '3.5 mm Audio Jack'). And for the RF or Video out a very standard RCA jack will do.

RCA Jack, switces and 3.5mm Audio jack
RCA Jack, switches and 3.5mm Audio jack

And finally the switches, which I already decided to be the the 'mini tactile switch, 6x6x5'.


Michael Wessel wrote 06/17/2019 at 14:28 point

Definitely try free routing! Much better than the KiCAD auto router.

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Cees Meijer wrote 06/17/2019 at 15:39 point

As I want to follow the original traces as much as possible, this is is definitely going to be a manual routing job. And hey, it's a hobby project , so time is not important...

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Ken Yap wrote 06/17/2019 at 12:18 point

Wow, that's a huge one. Having done a few smaller projects (<100x100mm) with pcbnew and freeRouting, I can say that I spent far far more time tuning the placement of the chips to reduce the trace lengths and the number of vias. Eventually you will find an arrangement of chips that makes the most sense in terms of signal flow.

I've updated my page about freeRouting here:

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Cees Meijer wrote 06/17/2019 at 15:40 point

I will follow placement and routing as close as possible to the original, so I do not have to think about that too much.

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Ken Yap wrote 06/17/2019 at 22:30 point

Good idea. You could go halfway, use the original component positions and let openRouting do the routing. It'll probaby do at least as well as the original.

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