Does anybody remember how these connect to a PC or XT? Obviously there is the DB37 which has the signals. On one version of the drive (the 720KB version) there is just the signal cable, and no power pigtail or external power - power must come through the DB37 cable, but the technical reference for the floppy controller doesn't have any pins that provide power. Was there a special card that passed the signal wires through and added +5 and +12 to the DB37 going to the drive? (Maybe on pins 1 - 4, which are supposed to be unused?) On the other version I have there is the power pigtail, which is obviously where the power comes from. The pins on the power pigtail are connected to pins 1 - 4 on the DB37. Mike

I found a little treasure trove of info .. I'm happier now. Models of the 4865 for the AT have just a DB37 connector. They are supposed to get power and signal from an additional card that goes into the machine, as an AT normally doesn't have an external floppy port. Models of the 4865 for the PC and XT have the pigtail power connector. There is a Y cable to split power from inside the machine to the drive, and a bracket that accommodates the new power plug that is needed by the pigtail connector. I traced the voltages out already, but getting confirmation was nice. If anybody ever has a desire to connect a 4865 to something, let me know. Mike

There's a PDP-11/45 console for sale on eBay. http://tinyurl.com/22jrue What's interesting is who's selling it: "I am the designer of this bit of computer history. It was in the days when computer architects wanted direct register access from the operator's console. It was a time of hand-keying in boot codes and other unbelievable tedious computer operations. It was also the time when customers expected more expensive computers to have more lights and switches. This was the zenith of DEC consoles (shared by the PDP11/70 18 months later). The innovation in this console was that the switch handle design was symmetrical and functioned equally well moving up from center or down from center. The Industrial Designer assigned to the project was unable to grasp the geometry of this trick, and as the project and electronic lead, I had to show him how to do it. Other than that he created wonderful asethetics and this is a great collectable over 30 years later. The schematic diagrams are available for additional negotiated fee. And so you know, the reason I'm selling this is that I have another. Ask any questions. Have never plugged it in, so don't know what works and what does not. But the logic is very primitive and anything could be easily repaired. Weight 15 pounds with packaging. Now very rare. And the only time you will ever be able to buy this from the designer." Cheers, jp

On 18 Sep 2007 at 20:26, Michael B. Brutman wrote: Compaticards (at leat the IV) have 4 jumpers to optionally apply power to those pins on the external drive connector. Cheers, Chuck