Yeah, Im with Arne. My clock always gains about 15 minutes every 2 weeks. I used to think that it stopped for 11.75 hours, but after I drove her every day for a month before I started on the suspension, I started to notice a trend.

Does the clock have one of the individual fuse holders that I see many of by trhe fuse block?

Many? As I recall only the radio and the blower motor have inline fuses. If the clock is not running I'd go with the overwhelming odds that the clock itself is simply not running.

Rear defroster also has an inline fuse, IIRC. Randy's clock is no doubt gummed up like so many are by now. I repaired the one in my yellow 240Z using the tips I found here:

Clock Repair: Analog 70-78 Z (Round)

Mike's right, they didn't come with an inline fuse for the clock. The only fuse for it is in the fuse block. Check the blue wire at the clock for 12V+ and check for ground. The other wire is for illumination. If that checks out OK, an internal clock repair/replacement is needed. I've got 3 clocks here I tested and 2 out of the three don't work....No surprise.

Well, at least I am in the same fine boat as most. I'll stick pulling the clock out on my weekend todo list. Hopefully I don't have many honey do's this weekend. I know, I'll tell my wife all I want for fathers day is a day to work on my Z! My two year old may not buy that though...