From my experience, certain more recent model Macs have been more
reliable than others; peripherals, not so much. Some scanners can last
except for driver support; printers and all-in-ones develop issues. Those
are not intended to last, and appear to be support vehicles to sell ink.
I've owned, repaired, and donated Macs off and on over a few decades.
Probably only about 400 or so. A few given to people I met who had need
for one or two. My most recent OS X is Mavericks 10.9(.5) only because
the last purchase (and third computer direct from Apple online) had that
and not the hoped-for older 10.8.5. The older OS X may have been less
of a gulf between other peripheral hardware than a later one.
My other desktop Macs include one remaining old PowerPC 7300/120
or some such similar build; it would need a new 3.6V battery to run &
has MacOS 8.6. Still have applications for some vintage; gave away so
much of the older stuff that I kinda feel sad because the later owners
may have no idea how hard it was to get those items, even then in AK.
To try a new keyboard or a known-good spare, is how I troubleshoot them.
And use wired keyboards to avoid 'startup keyboard shortcut' failures.
My two main Macs now are last model G4 Mac Mini 1.5GHz w/ 10.5.8;
& Late 2012 Mac Mini i7 intel quad server 2.3GHz with dual 1-TB HDDs.
Others include functional iBook G4 12-inch 1.33 last model, MacBook
intel coreduo 1.83GHz first model (all older Macs have Leopard 10.5.8)
+ three iMac G4 1.25GHz 17-inch USB2.0 models; require various fixes.
And one PowerBook G4 1.5GHz aluminum 12-inch w/ major issues.
Most if not all of my early Macs required repair before I could use them.
When in college, two courses required use of computers, but working
full time in a trade while attending college 14 credits per semester did
not allow me limited access computer lab time. An independent Mac
reseller in the town where the college was, had a few early Macintosh
models; but they declined to run my credit to see if I could finance...
With 50% down for a $3500 Macintosh 1984 model. After that, with
50% cash in hand, I bought a Yamaha Bravo snow machine instead;
& a Canon TypeStar7 electronic typewriter, whose pages looked better
than computer-printer ones from the college computer lab. As a bench
jeweler, who took a job at wholesale wages to afford college, I was
hard pressed to make schedules fit between full time in both places.
It was later on that I was given my first Macintosh. It needed parts and
an upgrade for me to try & make use; it did not work online or do email.
I'd try a different keyboard. A few mac-centric brands also still exist.
Or if you know Windows keyboards, they can be used OK in a pinch.
And consider an external optical drive such as owc macsales shows.
A bit of this and that. I have several spare (one new in box) keyboard
from vising moving sales as noted on craigslist; drove miles to find
the deal was a full sack of new Mac software plus new keyboard: $50.
So I may need to buy a new aluminum keyboard with upgrade to Sierra.
The world is a moving picture, take a frame at a time and slow motion
through it. These items should not be given the attention afforded them.
All this, & I still have two non-electric typewriters + a kerosene lamp.