Modifying SX-64 from NTSC to PAL

From: Marko Mäkelä (
Date: 2001-05-04 09:40:17

Since cbm-hackers doesn't allow postings from non-subscribers, I'm
forwarding this message for Alex:

[My answer to Alex: yes, you can use the 17.734472 MHz crystal from a
normal C64, but you will probably have hard time trying to find the
7.881984 MHz crystal.  You could try to use a 8 MHz crystal, but then the
picture would probably be somewhat distorted, and some disk fastloaders
wouldn't work.  If the only thing you want is to have PAL demos working
properly on the screen (in black and white), you could just swap the video
chip.  The built-in monitor might not synchronize to the approx. 50 Hz
input, but this is the easiest thing you can try.]

Date: Thu, 03 May 2001 19:25:32 +0200
From: Alex M <>
Subject: Modifying SX-64 from NTSC to PAL
In-Reply-To: <>
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Dear 64´ers!!!

First Thanx for your nice response!!!

For the PAL clock could I use a crystal coming from a PAL normal C64? I
have a board usable for removing components and doing testing...
I can try to find the 7.88Mhz one ... :/


At 11:00 03/05/01 +0200, you wrote:
>Marko Mäkelä wrote:
>> > So it gets more complicated than a normal C64...
>> As I don't have an SX-64 or the schematics for this subboard, I'm passing
>> a copy of this message to the cbm-hackers mailing list.  If there are no
>> PAL SX-64 owners on the list who could help you, you could try to
>> construct some sort of a schematic diagram for the subboard (even just the
>> part numbers would help a lot).
>I have both a PAL and NTSC SX-64, and I think that just the two crystals on
>the sub-board have to be swapped, because there is a dedicated crystal for
>both color and dot clock. The problem will be to get a matching dot clock
>crystal for the PAL mode, because it is something like 7.88MHz. This is much
>harder to get than the color clock crystal with 17.734 MHz, which also is not
>that easy to get. I would rather build a new oscillator sub-board from
>scratch, based on the C64B clock circuit that needs just the 8701 chip and a
>single (color clock) crystal.
>The other problem is the built-in display: It also is a different version and
>will not display color if you convert the C64 board to PAL. From what I've
>seen both displays use the same boards, but the NTSC board lacks some
>components, but other components will probably be of a different type. I do
>have a very bad copy of the PAL CRT schematics, but none of the NTSC type.
>Converting the display as well is not an option I fear.

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