Re: Converting a Commodore 64 from NTSC to PAL

From: Gerrit Heitsch <>
Date: Fri, 13 Apr 2012 15:13:40 +0200
Message-Id: <>
On 13.04.2012, at 14:47, wrote:

> On 2012-04-13, at 14:41, Gerrit Heitsch wrote:
>> The 50Hz or 60Hz derived from the 9V AC from the power supply is only used for the 2 CIAs and there only for the TOD which, as far as I know, is not used by the Basic or Kernal at all.
>> That doesn't mean that there won't be software that will detect whether it's running on PAL or NTSC, then uses the TOD and sets the divider Bit for the TOD wrong on a PAL C64 running in the USA.
> Yes - even if TOD clocks were (are) hardly ever used - if the OP wants full compatibility, this aspects also has to be taken care of in order to potentially avoid strange errors in least expected moments ;-)

Then disconnect the TOD signal from the 9V input and rig up a 555 as an oscillator that will give you 50Hz. Not very accurate, but it should do for almost all software.


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Received on 2012-04-13 14:00:04

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