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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: zx6r6 on July 06, 2005, 11:11:10 PM

Title: Will a 2.04 Rom work in a rev 5 A500?
Post by: zx6r6 on July 06, 2005, 11:11:10 PM

The subject says it all! Its a rev 5 500 with ocs and half meg agnus. With a (working) 2.04 rom I get a red screen at startup. If I change denise,agnus etc to the ecs versions will it work then?

cheers

p.s anyone want to sell me their Amiga One!?

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: rhino on July 06, 2005, 11:37:10 PM

Quote

Its a rev 5 500 with ocs and half meg agnus. With a (working) 2.04 rom I get a red screen at startup. If I change denise,agnus etc to the ecs versions will it work then?

IIRC older A500 motherboards needed a jumper link between two pins on the 2.04 ROM to work. The original upgrades were supplied with this jumper in place and it was to be snipped when installed in newer boards. If your ROM doesn't have a jumper you'll probably need to add one. The best reference I could find with a quick Google was this one:

http://www.titan.co.nz/amigaak/AA060127.htm (http://www.titan.co.nz/amigaak/AA060127.htm)

HTH

Robert

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: zx6r6 on July 06, 2005, 11:50:38 PM

Guess I'll have to change my search engine, I couldn't find any info! I'll give it a go tomorrow.
cheers for your help!

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: Argus on July 07, 2005, 12:39:05 AM

iirc you need to connect a small wire between pins 1 and 21 on the rom chip.

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: bloodmoney on July 07, 2005, 04:19:47 AM

That is incorrect I believe. Connect 1 to 31 should be correct. 1 to 21 is for 3.1 rom
kickstart (http://www.oldsoftware.com/kickstart.html) A metal bread tie and a solder iron will do.

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: zipper on July 07, 2005, 05:35:39 PM

2.x and 3.1 behave the same, needing the mod.

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: Generale on July 09, 2005, 09:56:50 AM

Ohhh...I see. So it needs the jumper wire for newer KS on the older boards.

Stupid question. I had a KS rom switcher kindly donated to me with an unknown KS on it. It didn't work with either of my r5 a500s. One of them has ks1.2 and the other has ks1.3. Neither has the jumper wire.

Would the wire do the trick? And is it 1->21 or 1->31?

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: zipper on July 09, 2005, 10:10:45 AM

(reading the official Rom update instructions:)

For ..and rev.5 boards, the ROM socket must have pin 1 connected to pin 31 and the ROM IC must have connected pin 21 to bent-up pin 31

(VillageTronic "English")

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: Generale on July 10, 2005, 04:45:04 PM

is there any real reason to do the pin 1->31 bridge on the socket? why not do both 1->31 & 31->21 on the ROM?

Title: Re: Will a 2.04 Rom work in a rev 5 A500?
Post by: melange on July 12, 2005, 10:27:21 AM

I have done the mod for the A500, it was simply pin 1 -> 31 on the rom.  I didn't have to bend any pins.  Just soldered a wire from pin 1 -> 31.  At least that's how I remember it.  Was a long time ago.