Having repaired one of those tin and zinc clocks at the last job
before redundancy,
$100 is a lot cheaper than the invoice for fixing your dead one.
I had to carefully craft a newly cut gear on the old mechanism.
This is, unfortunately a problem with fixing many vintage devices :-(
To get back to classic computers... Think of just about any machine that
you like, and think of the difference in price (Ebay if you like) betwen
a working example and a non-working one. Even for quite rare machines,
it's not that much. And now think how long it would take to fix the
non-working one (fiding the fualt, tracking down spares, soldering in the
componnts, etc). And thus work out what thest rpeairs would pay per hour.
That's why it's not worth the hassle of running a business for this.
On the other hand, fixing these machines is fun, and it's a great hobby.
Hobbies don';t make financial sense. So I am happy to cerry on fixing
things and to share my experiences
-tony