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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: da9000 on February 13, 2006, 01:25:13 PM

Title: can someone explain the A500 rev.5 + KS 2.04 hack?
Post by: da9000 on February 13, 2006, 01:25:13 PM

I've seen the KS 2.04 on the A500 rev.5 board has a wire between two pins: top left-most (pin 1?) and somewhere in the middle of the right side.

Why is this needed for the rev.5 boards (I saw it mentioned in another thread). Can you point me to any docs that explain this?

Also, on rev.6a motherboards there's a resistor going to the left-most CIA. Can you point me to any docs for this too? Do I need to do it in the rev.5 boards to "save" them from possible future CIA-deaths?

Thanks in advance

Title: Re: can someone explain the A500 rev.5 + KS 2.04 hack?
Post by: Amiga4k on February 13, 2006, 09:58:31 PM

For Rev 3 and Rev 5 boards, the 2.04 ROM IC must have pin 1 jumpered to pin 31. This connects A17 (pin 1 on the ROM chip) to A17 (pin 31 from PCB). For Rev 6A and above, cut or remove any jumpers from the top of the chip.

As for the resistor strapped on the ODD CIA at pin 5: Although I don't have a reason, it appeared on Rev5 type 3, and all Rev 6 boards. Anyone have that one?

Title: Re: can someone explain the A500 rev.5 + KS 2.04 hack?
Post by: da9000 on February 14, 2006, 08:53:23 AM

Thanks for the answer Amiga4k.

I guess the A17 address line is needed for addressing the larger 2.04 kickstart ?

As for rev.6a you mean that it's not needed and thus cut/remove the wire/jumper, correct?

Title: Re: can someone explain the A500 rev.5 + KS 2.04 hack?
Post by: Amiga4k on February 15, 2006, 02:06:16 AM

Yes, for Rev6a just snip the wire over the top of the ROM. I leave the wires, in-case I sell the chip later on.

No problem, I just research my technical database.

Title: Re: can someone explain the A500 rev.5 + KS 2.04 hack?
Post by: JLF65 on February 15, 2006, 02:50:35 AM

If you don't like hacking up the mobo, do like I did and get a low-profile socket. Remove the pin where you would have cut the mobo, and put the wire/resistor on the socket. Then just plug the modified socket into the mobo socket and the ROM into the hacked socket. Works great and no danger of screwing up the mobo.

Title: Re: can someone explain the A500 rev.5 + KS 2.04 hack?
Post by: da9000 on February 15, 2006, 03:55:12 AM

Good trick JLF65!

Thanks for sharing, although I have no qualms about hacking the motherboard :) I don't plan to get rid of my Amigas, (till death do us apart), but also I think hacked up hardware is way cooler :)
I remember I got my first Amiga, an A3000, and I looked in the back and there was a hacked NTSC/PAL switch attached to the rear.  I was so happy I had gotten a tweaked box ;)