Kicad conversion of the Thomson MO5

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stephen_usher
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Re: Kicad conversion of the Thomson MO5

Post by stephen_usher »

Desoldering using braid is *SO* labourious!

You really need a desoldering gun!
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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HigashiJun
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Re: Kicad conversion of the Thomson MO5

Post by HigashiJun »

stephen_usher wrote: Thu Sep 26, 2024 6:14 pm Desoldering using braid is *SO* labourious!

You really need a desoldering gun!
I have one, but using braid is my preferred method.
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Re: Kicad conversion of the Thomson MO5

Post by HigashiJun »

sporniket wrote: Thu Sep 26, 2024 6:03 pm 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...
Due to lack of space, I also have to set up a temporary workspace everytime I want to work on something and I agree with you, it's a real pain in the ...
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Re: Kicad conversion of the Thomson MO5

Post by sporniket »

stephen_usher wrote: Thu Sep 26, 2024 6:14 pm Desoldering using braid is *SO* labourious!

You really need a desoldering gun!
When I will have a big space where I can set up a workshop with with all those tools at the ready, I may consider.

But for now, I have found a sure way to perform desoldering that does not requires supplemental space for storage, and with a quite cheap TCO.
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Re: Kicad conversion of the Thomson MO5

Post by stephen_usher »

Indeed, though if you can afford it the Hakko FR-301 is a good solution as it's sold in a carry case and doesn't have a base station. You take it out when you need it, use it, let it cool and then put it in the compact case and then store it... but you pay for that convenience.

It does mean going from taking an hour to get one chip out (sometimes with a lot of swearing) to a couple of minutes though, with less chance of overheating and damaging the PCB.I must admit though that with chips with old solder which has flowed up the legs I still need a hot air station to free them without PCB damage.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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Re: Kicad conversion of the Thomson MO5

Post by sporniket »

I took me 15~20 minutes for the usual Logic chips, and the 40 pins eprom took around 30 minutes. For the logic chips I also took a session to straighten all the pins.

And no swearing.
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Re: Kicad conversion of the Thomson MO5

Post by sporniket »

I have finished the extraction of components from the donor motherboard. Next time I will reinstall the power supply elements and check how it goes.

2024-09-29--01-all-is-gone.jpg
2024-09-29--01-all-is-gone.jpg (324.24 KiB) Viewed 87 times

And I will be able to compile all my timelapses of the process and publish the video soon too.
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Re: Kicad conversion of the Thomson MO5

Post by sporniket »

The second timelapse, focused on extracting the components :



Copy of the description :

🎯 This year, I finished to convert the motherboard of the Thomson MO5 into Kicad. Now, I want to verify this work by actually build it.

➡️ The most tedious part. I experimented a lot of technique to desolder...

❌❌ Using ChipQuick SMD remover alloy... As the name says, it is for SMD only. On THT components, it just drip through the holes without helping much 💀💀💀

🤔 Using an electrically heated, manual solder pump... It works better than a manual solder pump in one hand, and a soldering iron in the other. Aspiration is better, but still weak. Then I had to finish, without ease, using a hollow needle. Some pads and traces were lifted, some pins were bent, one even brokes. Also, I hade to quickly change nozzles of the pump, and it finally ended up clogged anyway and I would need another heating element. So not as cheap as it seems at first, and not efficient, I DO NOT RECOMMEND ! 👎👎👎👎👎👎

✅✅✅ Using a wide (3/3.5 mm) solder braid AND A BIG IRON TIP was the winner tool, with a little bit of flux to make it flow better ! HIGHLY RECOMMAND ! 👍👍👍👍👍👍👍👍👍

💡 The video that made me realize that I needed a BIG TIP for my soldering iron in order to use solder braid successfully : 🔗

💡 The 900M-T-5C tip I bought (NOT SPONSORIZED) : 🔗 https://fr.aliexpress.com/item/1005005996377797.html

💡 The 3.5 mm width solder braid I bought (NOT SPONSORIZED) : 🔗 https://fr.aliexpress.com/item/1005007119153919.html
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Re: Kicad conversion of the Thomson MO5

Post by sporniket »

So, it works. At least the digital part of the motherboard, I had to bypass the power supply section to use a standard 5V/20W power adapter.





When installing all the chips, I had some that had a broken leg, so when it did not work at first, I tested continuity on those suspects, and one of them could not make contact with the socket. I forced the contact using a turned pin I had laying around for testing, I will do a proper fix later.

2024-10-20--02-quick-and-dirty-contact-fix.jpg
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HigashiJun
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Re: Kicad conversion of the Thomson MO5

Post by HigashiJun »

The end of your project seems not so far.
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