Kicad conversion of the Thomson MO5

[sporniket]

To change a little from the ST world, I started to convert into Kicad the Thomson MO5 computer, for now the v1 board (there are a v2 and v3 boards, that I plan to do later provided I am able to get one of those)

For now the schematic is done, and like the ST, I plan to remake the PCB. (This is one of my summer projects, along with the remake of the 260/520ST).

People can get the schematic in a nice PDF here : https://github.com/sporniket/kicad-conv ... .0.0-alpha

[sporniket]

Last month, I finished to replicate the PCB ( see there : https://github.com/sporniket/kicad-conv ... 0.0-beta-1 for all the files), and I received it today.

There are some little details to fix, but mecanically, it perfectly fit inside the case, and the mounting screws are at their expected locations. I need to do further check on the electric and mecanical side now.

2024-05-03--0-it-fits.jpg (205.51 KiB) Viewed 3248 times

[HigashiJun]

Well done !

Just kidding, but Fabius would be proud of you.

[sporniket]

Fabius would be proud of you.

So true

[sporniket]

This summer, I try to do an assembly, the goal is obviously to have a working computer as a proof of a correct remaking. The original computer will serve as donor board for the ICs, and especially the gate array (this is a Motorola MC1300 on a custom support, I will have to desolder it ; later iterations use an EFCIS gatearray in PLCC package put in a socket, more friendly).

Thus I ordered a big set of components :

2024-07-18--summer-project-in-bulk.jpg (59.87 KiB) Viewed 2871 times

Then I grouped them by type :

2024-07-19--01-resistors-and-ceramic-capacitors.jpg (77.2 KiB) Viewed 2871 times

2024-07-19--02-electrolytic-capacitors-transistors-diodes-inductances-cristal.jpg (78.6 KiB) Viewed 2871 times

2024-07-19--03-ic-sockets.jpg (62.03 KiB) Viewed 2871 times

And now I have started, first with most of diodes (the small ones, there is a power diode that will be put later, as it is big and have to stay at least 1cm above the PCB).

2024-07-28--diodes.jpg (197.07 KiB) Viewed 2871 times

Then the resistors

2024-07-29--02-done-resistors.jpg (280.83 KiB) Viewed 2871 times

To be continued...

[sporniket]

Done installing IC sockets.

[HigashiJun]

Looks good !

(And probably better than the original...)

[sporniket]

Thanks

The original board shows its age, espacially the underside where large copper pours have a wavy texture.

But the traces follow a quite clean orthogonal routing.

[HigashiJun]

Now if you find a mechanical keyboard for your machine (instead of the ugly chiclet keyboard...) and a good case, you will have a nice retro in your collection.

[sporniket]

This build will just use the case and keyboard of the donor computer. The rubber keyboard is not the best, but it's part of the nostalgia . I did not know about the "mechanical" keyboard version until I rekindled with that family of computer.

Today's progress : first adding the non polarized capacitors, as well as the cristal and the coated inductance :

2024-07-31--01-capacitors-inductance-cristal.jpg (277.64 KiB) Viewed 2766 times

...then adding the transistors and the electrolytic capacitors...

2024-07-31--02-transistors-electrolytic-capacitors.jpg (261.62 KiB) Viewed 2766 times

And the next step will be pulling all the chips from the donor board.

I have also prepared (not soldered yet) a socket for the gate array by hacking some DIP double-swipes sockets (get individual rows and sanding the ones that are on the inside.

2024-07-31--03-experimental-plcc-staggered-double-swipes-socket.jpg (83.34 KiB) Viewed 2766 times

It would be nice if the gate array is happy with it. I also have turned pins stripes, but it is more a hassle to use, so it's my fallback plan.