On Tue, Feb 22, 2011 at 10:45 AM, Malcolm Lear <malc...@essex.ac.uk> wrote:
> > > On 22/02/2011 16:26, Tony Firshman wrote: > >> Phill Harvey-Smith wrote, on 22/Feb/11 16:18 | Feb22: >> >>> David Tubbs wrote: >>> >>>> At 09:48 22/02/2011 +0000, you wrote: >>>> >>>>> On the subject of backplanes...... >>>>> >>>>> I have one of these : >>>>> >>>>> http://www.rwapadventures.com/images/q+4-interface.jpg >>>>> >>>>> But alas don't have the little interface board that connects it to >>>>> the QL, does anyone have one that can take a couple of high quality >>>>> piccies of it, or beter still have a schematic ? >>>>> >>>> >>>> Surely you you just plug it into the QL, mem'expansion or just ribbon >>>> cable. >>>> >>> >>> Well yes but perhaps I didn't make it clear, I don't have the small card >>> pictured on the left of that picture, just the big metal 4 slot >>> backplane.... and that deffo won't plug directly into the QL the cable's >>> not long enough....... >>> >> ... but I wouldn't bother even trying. >> This Quad device is about the worst electrically if I remember correctly. >> It was also pretty bad mechanically. >> >> I don't think they realised how noisy the QL bus was when extended. >> >> I'm not sure that's a problem. We had a lab full of QL's here at Essex > University each fitted with an adapter bringing ribbon cable out to a full > width 3U rack. The racks had memory, floppy, parallel, serial, and IO cards. > All worked without any problems. However the card at the QL end had full > data and address buffers. I've just checked and the ribbon cable was about a > foot long plus of course the length of the rack (18 inches). I've done a rough schematic for a 1 to 3 backplane with a 24 pin ATX connector with power control. This will work in any ATX case with an ATX2.X PSU - which would open up case options considerably. It does not contain a ROM socket like the Mplane, because it places two cards on the front side of the QL, not the rear side covering the ROM port. I will have a prototype made for testing in a couple of months, and will then share the photographs, schematic and PCB gerbers with the list. *If anyone wants a backplane, they can have a new TF Services MPlane for around £50/€60** including shipping** to the EU. As there will be a limited number before the ~50 PCBs are used up, if people would like to be on the waiting list they should email me. Please say in the email how many you would like reserved for you. These will likely be ready to ship in 6-8 weeks.* * * Dave _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
