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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: LoadWB on August 12, 2007, 06:26:53 AM
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I think AmigaKit mentioned before that the main obstacle to implementing an ATX PSU converter for the 2000 is designing a TICK signal generator. (I have an mini-ATX PSU in my 4000, and it's great!)
While browsing the A2000 Schematics I noticed J300, which selects between the TICK signal from the power supply and (the schematics are in another room, so I'm relying on recall here) the VBLANK signal.
Would it be such an issue to use the VBLANK signal in lieu of the missing TICK signal from an ATX power supply? Wouldn't that only make a difference with the internal clock when the system is in a video signal mode opposite of its native mode (PAL->NTSC, NTSC->PAL)?
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LoadWB wrote:
While browsing the A2000 Schematics I noticed J300, which selects between the TICK signal from the power supply and (the schematics are in another room, so I'm relying on recall here) the VBLANK signal.
Would it be such an issue to use the VBLANK signal in lieu of the missing TICK signal from an ATX power supply? Wouldn't that only make a difference with the internal clock when the system is in a video signal mode opposite of its native mode (PAL->NTSC, NTSC->PAL)?
I use this method for my A3000. I have a 300w AT power supply, providing power and had to use this jumper on the motherboard. The ami, works great and as it should (I don't do video work though, and use a cybervision rtg graphics card for non amiga modes).
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there are simple schematics on aminet for tick signal generator, and here (http://tesla.rcub.bg.ac.yu/~dragic/Amiga/Amiga_PCB.htm) in PROTEL format
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I have a ATX powersupply in my A2000 because my old PSU was overloaded, and i use "internal tick" and it works fine for me. :-)