Kicad conversion of the Thomson MO5

[tOriman]

@sporniket

Impressive!

tOri

[sporniket]

Thanks. I Hope to get good résultats soon.

[sporniket]

I have to wait for replacement nozzles for my desoldering pump as well as hollow needles for desoldering as I broke them, so desoldering the ICs from the donor board will have to wait.

But I have succedded in desoldering the gate-array without problem.

2024-08-01--01-desoldered-gate-array.jpg (88.39 KiB) Viewed 2450 times

For the other ICs, it will not be that easy, are most pins were bended before soldering.

In the meantime, here is the timelapse of the assembly so far :

[HigashiJun]

So far so good !

[sporniket]

Yes, it's the easy part of the build.

Extracting the chips from the motheboard will be more a hassle than usual, because the pins are bent for better grip.

[HigashiJun]

Yes, it's the easy part of the build.

Extracting the chips from the motheboard will be more a hassle than usual, because the pins are bent for better grip.

Oh yeah, I know what you mean...

[sporniket]

After receiving some supplies, I continued the process of extracting the chips.

But first, I have trimmed and rewritten the stickers that I put on the chips to identify each of them

2024-08-15--01-identify-chips.jpg (299.5 KiB) Viewed 2180 times

Then I used my soldering iron to unbend the pins, then used the soldering iron and a 0.8 mm hollow needle to detach each pin. I put flux to have better thermal conduction. With each chip, I gained valuable experience and refined my touch, and have less and less bend pins to straighten afterwards

2024-08-15--02-harvest-of-the-day.jpg (108.73 KiB) Viewed 2180 times

24-08-17--01-extraction-of-the-day.jpg (103.07 KiB) Viewed 2180 times

I have done all the chips where I already pumped the solder, for the next session, I have unbend the pins as well as added some fresh tin. I expect that when I will use my desoldering pump, I will better remove the tin and have less trouble with the hollow needle.

24-08-17--02-unbending-pins-and-fresh-tin.jpg (94.72 KiB) Viewed 2180 times

And by the way, here is my super advanced contraption to capture the timelapse of all this project : a stack of boxes, with a cheap mobile stand and a small light ring to remove shadows.

24-08-17--03-making-of-camera-stand.jpg (203.13 KiB) Viewed 2180 times

[sporniket]

little by little, I have extracted almost all the components from the donor board. Remains some key components of the power supply, the cartridge port and the tape drive port. Then I will finish and test the power supply part, and if its good, I will complete it.

2024-09-22--01-I52-I53-B4-B5-PM01.jpg (266.25 KiB) Viewed 1817 times

My winning combo to desolder components : a broad desoldering braid (3.5mm), and very big soldering tip (I have a 5mm diameter cylinder cut at an angle). The later is key to have enough thermal reserve so that it just work. A bit of tacky flux for better thermal conductivity may help, but finally maybe not needed.

On solder side, I remove solder from both side of each pin, and on the component side, I remove the remaining solder and press lightly against the pin to make it wiggle a little, and finally the component is just totally unstuck. It was very satisfying.

[HigashiJun]

On solder side, I remove solder from both side of each pin, and on the component side, I remove the remaining solder and press lightly against the pin to make it wiggle a little, and finally the component is just totally unstuck. It was very satisfying.

Same for me here...

Time consuming but effective method.

1 or 2 chips to remove are OK, but when you have to remove all the components from the motherboard, the satisfaction becomes a hassle.

[sporniket]

I usually cannot work on that more than 1 hour in the morning on the weekend, so up to 3-4 chips per session at best. The real hassle for me is the up to another hour (cumulated time, actual or perceived) spend setting up the temporary workspace before and cleaning after...