Might as well ask Archimedes to send a probe.
Hell, I'm not even sure we can make a computer that actually lasts 100 years.
I'm pretty sure we can. I have a 40-year-old calculator that is still working just fine.
Still, I was probably too ambitious when I said "computer". I was thinking more that we can't make a PC or server-style computer that would actually last 100 years, while in regular operation.
Also, 1980s calculators have much, much fewer moving parts than today's computers. They don't have any kind of active cooling, they don't go through rapid heating and cooling cycles, they probably have three orders of magnitude less electrical components than a modern PC.
For me at least, all of the PCs I have had so far have had a few electrical components giving out after at most 10 years (usually some condensers leaked).
In fact, it would not surprise me a bit if you could run a Raspberry Pi Zero for 100 years.
I wouldn't even be convinced then that we have the technology today. Any repair system would necessarily suffer from the same kinds of failures.
The real problems are political, technological and ecological stability.
No one has ever built electronics capable of lasting hundreds of thousands of years. It's not obvious if it's possible because on those timescales everything crumbles to dust, especially if it's constantly being abraded by dust and radiation.
And if you don't put your travellers into long-term suspension, political and cultural stability are even more fragile.
And small eco-systems are far less resilient than planet-sized systems - which, it turns out, may not be resilient at all on longer timescales.
So the gap between launching Voyager I/II and launching a self-replicating probe which can reproduce itself physically and culturally is beyond huge.
If you happen to have massive amounts of energy some of these problems get easier, because you can get where you're going more quickly. But some remain immensely difficult.
Which is why percolation is a much better model. There will inevitably be some attrition in any colonisation program, and there may well be a hard limit on the amount of entropy any colonisation program can survive.