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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: cv643d on September 06, 2006, 05:58:33 PM
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I have made a homemade Zorro 2 slot for an Amiga 500. I simply wired 1 from the expansion port of the A500 to 1 on the Zorro 2 slot and so on to 86.
Now I have read somewhere that most A2000 cards should work in an 86 pin Zorro 2 slot but so far all three Z2 memory boards (that work in my A2000) I have tried have not worked! (MAST, C= 2/8 MB board).
So I read about Zorro hacks on the Aminet and found out that I should perhaps connect pin 94 of the Zorro 2 slot to pin 11 on the 74LS32 chip under the floppy drive, but still the same results, no card work :-/
I still have some Zorro cards to try but I don’t know if I want to fry a CV64-3D or a Buddah controller.
Have anyone got some advice to get it working?
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Should work if it's done correctly. I'd check your connections carefully to make sure they are not reversed.
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I just checked everything again. I did not check each wire because I am almost 100% sure that pin 1 on the A500 expansion slot goes to pin 1 on the Zorro adapter and so on.
I soldered 1,3,5,7 and so on on one side, and 2,4,6,8.. and so on, on one side of the Zorro slot. Now I asume that Pin 1 on the mobo is the same as Pin 1 on the Zorro slot.
I did not do anything with the pins over Pin 86 this time, but perhaps I should ground every ground pin over Pin 86?
The Zorro cards do get slightly warm over some of the chips when I try them, but they show up as 0 MB fast :(
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About 11 years ago I built my own Zorro slot for the 500 and used a ZII GVP SCSI/Memory card to run a BBS. Worked great until the GVP card died 3 years later. The expansion I built required one logic chip added to take care of some kind of buss polarity or busy/ready signal. I did not wire the expansoin card to a logic chip on the motherboard as you mention with the 74ls32. I added the extra chip to the card I built. I got the info/schematics from aminet. The doc is still probably out there. Now I'm going to have to dig that old card out and have another look after all these years.
Here we go, this looks like the doc I used. It lists a 74ls86 as a required part. That sounds about right.
http://main.aminet.net/pub/aminet/hard/hack/2000slot.lha (http://main.aminet.net/pub/aminet/hard/hack/2000slot.lha)
Plaz
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Ah, finally someone who built one..
I am going to follow that doc when I try it again.
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I too have buildt one. My A500+ has an internal zorroII scsi-card with 2MB fastRam and HD. I did not use any extra chip tough I remember it was recommended, I followed some instructions on Aminet, and It worked right away. It slowed down the computer abit tough, and if I query the scsi-device the whole thing hangs. The GVP software works ok, however. Maybe the missing logical chip would correct that, not sure what it is for.
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Im curious, is that a full length Z2 card that you have fitted inside your A500.
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Yes, it is. It was extreamly tight, unfortunatly i had to cut out an opening in the chassie for the hd. When I made this hack, I was not aware of Half lenght cards but back then I would not have money for anyone anyway, this card I got for free!
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Hi,
I will send you a scan of a cct diagram for A500 to
Zorro2 if you contact me at: shaunwaller@ntlworld.com
Have fun.. :-)
Wol.
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I have been measuring with my eye if a cv64-3D could fit inside the A500. But I think a smaller SFF case would be a better choise, since the card runs hot.
@Wol
Thank you, you sent that article to me in another thread :-)
It was interesting to read and it is that article that got me inspired to make an 86 pin Zorro slot (without chips or circuits) since they said many cards would work fine on it.
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Yes, I finally got it to work! My 2 MB C= board is showing up as 2 MB fast RAM :D
Disconnectec some wires that didnt match (checked http://gd.tuwien.ac.at/hw-related/hwb/co_ZorroII.html) and connected pin 94 on the Zorro slot to pin 53 on the expansion port, I am happy :)