Re: Apple IIe (European/PAL) recovery

[Danilo Larizza <dlarizza@tiscalinet.it>]

ookkk :)

the cpu is ok.....i try it with a Commodore Floppy disk 1541 (have a 
6502 inside).

with your experiment i can try the crystal...

thankssss


Il 16/04/2013 08:38, barrym95838 ha scritto:
> > heeeelllpppp :)
>
> If you don't have a working machine for chip-swapping, you can try this little experiment.  This must be done carefully!
>
> Remove all cards, ROMs, and RAMs, and hard-wire D7 .. D0 with %11101010.  This is the 6502's NOP instruction, and should cause A15 .. A0 to act like an expensive 500 kHz binary counter.  With your DVOM set to frequency, check A15.  A0 will be 500 kHZ, A1 will be 250 kHz, ... , A15 should be about 15 Hz.  If this checks out, then your crystal and 6502 check out okay, and you will have to look at some of the support chips.
>
> Hope this helps!  Good luck.
>
> Mike