From: David Salamon Subject: Re: Expanding ISA slots in an A3000 Here is Jeff Wille's info on adding a third PC slot to your A3000. I have a couple of pointers. First, the XT or AT connectors from Radio Shack (solder tail version) work well for this and they are cheap. Second, I strongly recommend using a 64 pin "insulation displacement" edge card connector as your extra slot instead of another XT connector, since the edge card connector can just press onto the ribbon cable and save you half of the soldering job. Since the XT connector is only 62 pins, you have a little space at the end on the 64 pin edge card connector, but so what. Good luck! David HOW TO ADD A 3RD INTERNAL IBM AT/XT SLOT TO YOUR AMIGA 3000 - Jeff Wille ----------------------------------------------------------- This describes how to build a connector that allows the lowest slot in the A3000 to be used as an IBM AT or XT slot. (BTW, I take no responsibility for you or your A3000 should you fry either one. I've only done this for an XT slot, but an AT slot should be a straight-forward extension of these instructions.) It's relatively easy, inexpensive (< $15 probably) and it shouldn't void your warranty since you don't have to make any changes to the computer itself. Basically what you do is make a Y connector which plugs into the lowest IBM slot (which is the next-to-the-lowest slot). The lowest slot is an Amiga slot and that's where you put your 3rd IBM board. If you make it compact, you can still put the cover back on your A3000 with your boards plugged into it (unless you have very tall boards.) First you need a card-edge (with terminals) which will plug into the IBM slot. What I did was get an old parallel interface board and cut off the part with the card-edge terminals with a hack saw. If you want to make an AT slot, get an AT style board (with two sets of terminals). But then you knew that, right? Make sure you get one that has nice solder pads on it. It will make your life easier. Next you will need two card-edge connectors (4 for an AT slot). I got mine from a dead AT motherboard, although I'm sure you could buy these parts new if you wanted to. Connect each terminal of the card edge to the corresponding contacts on the card- edge connectors with a short (~1.5 inch) piece of ribbon cable. In other words, hook everything up in parallel, pin 1 to pin 1 to pin 1, pin 2 to pin 2 to pin 2, etc. That's basically it. To make it very compact you can bend the leads of one of the edge connectors inward and solder them directly onto the card edge and only run the ribbon cable to the second connector. If your 3rd board consumes a lot of power, you will want to make the following additions suggested by Dave Haynie. I had to do this to get my Data Acquision and Motion Controller boards to work reliably. (It's probably not a bad idea to do this in any case.) Run heavier wire for the +5V and GND connections. Pins B1 and B31 are GND, and pins B3 and B29 are +5V. The B pins are on the solder side of the board. Then put a 0.1 uF capacitor between B1 and B3, and another between B29 and B31. IMPORTANT NOTE: Once you are finished, make sure you test all of your connectors to make sure everything's hooked up right and you haven't made any solder bridges. Plug the card edge into the lowest IBM slot and plug two IBM boards into the card-edge connectors. You will not be able to use the normal retaining screws to hold your boards in place and ground them, because the boards won't slide in all the way. So, you can either put in a spacer (standoff) and put a screw into that, or just run a grounding wire from the chassis to the port cover (or whatever the metal end of the board is called). With this technique I am currently running an AT bridgeboard, a Data Translation data acquisition board, and a Galil 3-axis servo motion controller board simultaneously. Good luck. --------------------------------------------------------------------- Jeff Wille