Tales of a poor battery-bombed SIS-471-G 486 motherboard…

mmu_man

Tinkerer
Jan 30, 2022
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Two weeks ago I took this 486 away from its 25 years sleep at my mum's attic… It was quite well stored and covered, except little did I know back then about Varta, Destroyer of Worlds.


Close-up view of the motherboard with a missing battery, a broken ceramic cap, and components coverev in green stuff.


I then spent way too much time cleaning it, removing components


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checking and fixing traces


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fixing vias…

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fixing more traces


testing them, and coating them with solder mask…


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I even redid the missing silkscreen references, because I still had sleep to skip I suppose…

And I dug one of the missing pads to find the ground plane and fix it.

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Then I cleaned up the components, most could be reused (I added a socket for the IC as it was clearly loosing legs).

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And during Dave's stream I assembled it back:


And fried a tantalum cap.

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But guess what: it worked \o/

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It better be, after all those hours. I added a crude CR2032 mod and assembled the case:

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And I was greeted with a working hard drive, now I remember customizing the autoexec sequence to look like Linux boot from the era. 😅


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I'll quickly image the disk just in case, but I'm quite pleased how it worked out, I just hoped I'd spend less hours on it. 😁
 
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