[vcf-midatlantic] PAL c64 - Power supply

Bill Degnan billdegnan at gmail.com
Mon Jun 18 07:41:37 EDT 2018

On Sun, Jun 17, 2018 at 11:44 PM Jonathan Gevaryahu via vcf-midatlantic <
vcf-midatlantic at lists.vcfed.org> wrote:

> There is one "Gotcha" to be aware of if driving a PAL c64 from an NTSC
> psu in the USA:
> Because the 9VAC input to the c64 is derived from a linear power
> transformer, the TOD "RTC" interrupt to one of the CIA chips will be at
> 60hz, not 50hz, so any software which depends on that "clock" circuit
> incrementing at 50hz will be wrong.
> On 6/17/2018 10:21 PM, Bill Loguidice via vcf-midatlantic wrote:
> > I use an American power supply on my PAL C-64. No issues. Same thing on
> the
> > Atari 8-bit side.
> >
As long as everything south of the step up/down transformer is consistent
(all PAL or all NTSC) you'll be fine.  Otherwise yes you'll have to replace
the crystal and the VIC II chip if you want to use a NTSC monitor plugged
into a regular NorthAmerican plug, with a PAL machine plugged into a step
down transformer.

In the case of my P500 exhibit at VCF whatever I replaced the crystal and
VIC-II chips so I could use any display plugged into a standard socket.

Oh and remember you'll need a PAL 1541 disk drive also attached to the step
down transformer drives are also incompatible


More information about the vcf-midatlantic mailing list