I have the issue with the clock and I think most Z users have had an issue if there car is high mileage and the clock has been in use enough to blow. I took apart my clock this weekend and saw a "tuft" of carbonlike marking underneath the digital face (the red covering is off at this point). I knew something overloaded and decided, to do what a lot of people do, to either purchase a cool clock to replace that is gonna match my interior lighting from any kinda car (mine will be blue digital) or you can place a turbo timer in the slot as I see a lot of TT guys do (since it usually fits nicely). Seeing as your N/A, yea.... nvm on that last one
I don't think you should count on the clock working again, check it like I did and let me know what you see. I think it is a rather large defect among Z owners and ppl sell the used clocks on ebay for around 30 bucks, which is a lot for a clock you know will break the same exact way.
If you can't get power to your head unit, check to make sure you wired her correctly. The Z, in my experience I guess, has a nasty way of making colors "hot" that don't seem like they should be at times and likes to be tricky with different wire colors for different years I hear. So get a old 12v bulb with hot and ground out to test. The clock's yellow wire is power and I think your head unit sould be the same. My clock had all power in the right places, the clock was blown. My head unit never had a bout with me yet, so I find your situation peculiar.
Ok, so my advice there seems cheap and not helping enough to me so here is something I used cause the bose system was a little hassle to yank out when I redid my entire system in alpines last summer. This link has actual 300zx pictures and will help you a lot more to your stereo install. If you absolutely review this and have head unit trouble still I'm at a loss. ALSO attached is the fuse panel diagram incase yours was lost, I'm posting it for all Z ppl cause god I didn't have one for the longest time and it was hard to find.... check it to make sure u got the right fuse
BTW everyone installdoctor has tons of diagrams, very nice instruction for most cars
http://www.installdr.com/Insta...5.pdf
If you can follow the linkg. If your really not able to go to that for some reason, the list I have here for the stereo is:
Mem:RED/BLK
Pwr:BLUE
Front Speaker(s)
RF(+):BROWN
RF(-):BRN/WHI
LF(+):BLU/WHI
LF(-):BLU/YEL
RR(+):BLUE
RR(-):PINK
LR(+):RED
LR(-):GREEN
Hope any of this helps