Well, there were black Star Trek characters other than La Forge. Uhura seemed pretty bright, along with Sisko and Tuvok and there that’s helmsman on Enterprise. Tuvok especially fits the OP’s bill.
Would Sydney Poitier’s doctor character from Guess Who’s Coming to Dinner count?
Mayweather? Porthos, the captain’s dog, gets more lines than he does.
But at least Dr. Dyson dies heroically, saving our heroes. I’m always so sad when he blows up. (yeah, I watch that movie regularly 
)
Well, not really. Although played by an African American actor the character of Tuvok was not “African raced” as per the OP…he wasn’t even human.
Just remembered, Joe Adams played a psychiatrist in The Manchurian Candidate (1962). He gives Frank Sinatra some observations (as well as solitaire advice) about why Laurence Harvey’s character is so screwed up. He blames the mother.
No that was a dissapointment the tests were allways carried out by the quite nerdy white friend of his (remember the lab scene when the nerd described the violin as accoustically perfect to Samuel L. Jackson) Jackson’s character was more of a historical detective, sertainly very bright, but not someone for a minority young Einstein to look up to as a role model.
Angela Bassett played a sharp, gutsy Chief Medical Officer in “Supernova.”
You sound just like my wife (who is black). I say it’s just as likely that he’s Asian.
Next thing you know you’ll be claiming Destro in GI Joe is black. 
Oh, yeah… Angela Basset also played one of the President’s scientific advisors in CONTACT.
N’Bushe Wright played Dr. Karen Jenson, the coroner who dabbled in making vampire-subsititute blood serums in BLADE.
And as a cerebrally enhanced Simon Phoenix in DEMOLITION MAN, Wesley Snipes emerges from suspended animation with new martial arts skills and cmputer interfacing abilities.
How about computer hackers? The hacker bad guy in **Die Hard ** was black. Sure, he died eventually, but then all the bad guys did.
The “Jones” character from The Hunt for Red October was a serious geek, albeit on a sub – listening to classical music and ID’ing singing and silent caterpillar drives in the same shift…
And I’m sure there was a computer hacker bad guy in some flick about a ship that gets hijacked (sea-jacked?), but darned if I can remember what it was.
Actually, he didn’t and was the only bad guy known to survive (some of the others were shot, but their deaths are unconfirmed). He was punched out by the limo driver (also black, incidentally) while preparing an ambulance-driving getaway. How all 13 terrorists/theives were planning to escape in this one ambulance is unclear.
N’Bushe Wright was the haemotologist in Blade.
That guy (Theo)was cool.
And…on the recent Ninja Turtles revival cartoon, Baxter Stockman, an evil mad scientist, was black. And from what I saw—which wasn’t too much, admittedly—he wasn’t played for laughs.
Well, hey, in the original “Mission: Impossible” series, Greg Morris played Barney Collier, the ultimate technician.
In “Terminator 2,” the brilliant engineer who revolutionizes the world (and in the process, lays the foundation for machines to take over) is black.
Orlando Jones was a science professor (and women’s volleyball coach) in Evolution. Crappy film, but it counts.
The mathematician in Chrichton’s Sphere was black and they made a movie out of it.
…and the guy in The Core. Admittedly, people lambasted the movie, and he was presented as somewhat ridiculed, but he was right, and he really did build that stupid ship.
I’m a big Adult Swim geek.* I have a Sealab 2021 t-shirt, but I noticed every time I wore it in public, Black kids would come up to me and tell me they loved the show and wanted to know where I got the shirt** Finally I figured out that the reason it was so popular was Dr Quinn. He’s the only smart character on the show, he’s banging the only hot chick on the show, and he’s Black.
*Hell, I’m just a big geek period. But that’s beside the point. Hence the footnote.
**Hot Topic. I’m not proud.
Valerie from the old Josie and the Pussycats cartoon was an uber-smart tech geek.
Well, she was.
I was just gonna mention Dr. Quinn, vibrotronica. Remember when he wrote the essay on why he should father Debbie’s child. Damn, son! 
Also, in the same vein, Frylock is prettymuch a genius geek. He’s also a giant box of fries, but I think the blackness can be seen.