This may be a silly question, but: Could I use an NTSC-VIC chip (6560) in a PAL-machine or would I run into problems? The PAL-machine has 220V, 50Hz, while an NTSC-machine would have 110V, 60Hz for power supply. Would the VIC-chip "care"? Is the NTSC-board different from the PAL-board?
If switching chips is possible, my dream would be to mount them both on a switchable board to just flip your machine from PAL to NTSC... possible?
I know the NTSC-ROM is slightly different for screen positions, but one could either switch the ROMs as well or just disregard that effect.
NTSC-VIC in PAL-machine?
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eslapion
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The power supply is truly not an issue.
On the 2-prong, what is actually delivered to the VIC is 9-11Vac while on the VIC-20 Cr, you get 5Vdc and 9 Vac.
The above is true for both PAL and NTSC machines. You may have a bit of an issue with the 2-Prong as the connector is slightly different but otherwise, everything is fine.
Now here comes the big trouble. All the clock signals in the NTSC VIC are decimated from a 14.31818MHz crystal while on the PAL machine it comes from a 8.867Mhz crystal. The value of many resistors and capacitors needed to create the proper clock signal are completely different.
You also mentioned the kernal ROM isn't the same. You could do just like JiffyDOS and have both versions on the same chip and toggle them with a switch.
There's also the values of the capacitors and resistors (and some cases inductors) that filter and mixes the video signal that are different as color encoding is done at a different frequency.
Having both a PAL and NTSC VIC-20 with board no. 324003, I can tell you that apparently, as long as you have two VICs with the same "generation" or revision of boards, they are identical but there are so many components both analog and digital that are different that it's a nightmare to simply toggle from one another.
You certainly can't simply toggle between a 6560 and 6561.
On the 2-prong, what is actually delivered to the VIC is 9-11Vac while on the VIC-20 Cr, you get 5Vdc and 9 Vac.
The above is true for both PAL and NTSC machines. You may have a bit of an issue with the 2-Prong as the connector is slightly different but otherwise, everything is fine.
Now here comes the big trouble. All the clock signals in the NTSC VIC are decimated from a 14.31818MHz crystal while on the PAL machine it comes from a 8.867Mhz crystal. The value of many resistors and capacitors needed to create the proper clock signal are completely different.
You also mentioned the kernal ROM isn't the same. You could do just like JiffyDOS and have both versions on the same chip and toggle them with a switch.
There's also the values of the capacitors and resistors (and some cases inductors) that filter and mixes the video signal that are different as color encoding is done at a different frequency.
Having both a PAL and NTSC VIC-20 with board no. 324003, I can tell you that apparently, as long as you have two VICs with the same "generation" or revision of boards, they are identical but there are so many components both analog and digital that are different that it's a nightmare to simply toggle from one another.
You certainly can't simply toggle between a 6560 and 6561.
Be normal.
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Mayhem
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Yes, there are.tokra wrote:Are there even NTSC VIC-20s with round DIN-power-connectors?
Having a few of those,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug