Hmmm.. Technics 30 years old, Yamaha 24 years... specifications are irrelevant at such age (although Technics looks more advanced)... both can stop working at any time in near future (it's quite possible that they already don't work flawlessly)...
I would say neither of these two.
As for learning, there's no need for the first keyboard to be something fancy... but it should work as intended, so we can actually use it for learning how to play. I don't say it must be new, but 20+ years is a bit too much, I think.
What I'm saying is, if someone is really interested on learning how to play on keyboard, then (s)he should be ready to pay at least a minimal amount of money.
For example, new
Casio CT-X700 is
only 230€ and can serve for years -long enough to learn and see if keyboard playing is your future hobby.
Just my opinion,
Bogdan