An update, I made the HDD PCB for the Tecra 520 > 550 series laptops and it works on my Tecra 520CDT - see that mess of wires? That's what I was using prior and it keeps breaking:

It's very definitely version 1 - I had a deadline for making it and after declaring it done and comparing it with the original I found that the HDD connector on the thin end was backwards... I had to re-do it and finally put this out at 4am dead tired. It means the compactflash doesn't have a lot of space to work with and probably no other type of drive would work.
I think it can be resolved by using a cable but the dimensional constraints of the Tecra 520/30/40/50 are very limited so only the original flex cable can properly fit with the caddy.

Thermalwrong wrote on 2025-05-19, 21:17:

An update, I made the HDD PCB for the Tecra 520 > 550 series laptops and it works on my Tecra 520CDT - see that mess of wires? T […]
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An update, I made the HDD PCB for the Tecra 520 > 550 series laptops and it works on my Tecra 520CDT - see that mess of wires? That's what I was using prior and it keeps breaking:

The attachment CaddyHack (3).JPG is no longer available

It's very definitely version 1 - I had a deadline for making it and after declaring it done and comparing it with the original I found that the HDD connector on the thin end was backwards... I had to re-do it and finally put this out at 4am dead tired. It means the compactflash doesn't have a lot of space to work with and probably no other type of drive would work.
I think it can be resolved by using a cable but the dimensional constraints of the Tecra 520/30/40/50 are very limited so only the original flex cable can properly fit with the caddy.

I’m interested in this adapter board project for my Tecra 530CDT, by any chance was there a release of your project? (hopefully v2 with the correct orientation!)