mine does that. always has. wait. oh, right. i don't know what a z80 is.
I got to admit when I first read it though on ZX80 Spectrum, but then I went seeking and I got this results:
* Radio Shack TRS-80
* Sinclair ZX80, ZX81, and ZX Spectrum
* Amstrad CPC and PCW series
* MicroBee
* The MSX standard home computers
* Spectravideo SV-318, SV-328 and successors
* Jupiter Ace
* Sharp MZ
* MGT (Miles Gordon Technology) SAM Coupé
* Commodore 128
Well rather then being a computer Z80 is a processor line used on the above computers
