jboggs@inco.UUCP (John Boggs) (04/10/90)
Last week I bought a new floppy disk controller and a 3.5" 1.44Meg drive for my XT clone. The installation was fairly simple but I ran into a problem. The controller documentation (SYSGEN Omni-Bridge) was excellent and provided a lot of info on drives in general but it lacked one significant point. When I installed the new drive, I wanted it to be the A: drive so I removed my old A: drive, left the old B: drive in place, and installed the new 1.44M drive as A:. When I booted the system, the new A: worked fine but the old B: kept giving me a "not ready" error. The SYSGEN manual talked about cable terminators (terminating resistors) and said that, when mixing a 5.25 and 3.5 inch drives, the terminator should be in the 5.25 no matter whether it is first or second on the controller cable. When I put the terminator in, neither drive worked. After messing with different things and re-checking all jumper and switch settings I decided to switch the drives around (let the 5.25" be A: and the 3.5" be B:). When I did this, everything worked fine but only if I left the terminator out completely. Can anyone explain what was going on here. It all works now, but I'd like to understand it so I won't make the same mistake the next time. Thanks, JB -- John Boggs McDonnell Douglas Electronic Systems Company McLean, Virginia, USA
keithe@tekgvs.LABS.TEK.COM (Keith Ericson) (04/14/90)
In article <7946@inco.UUCP> jboggs@inco.UUCP (John Boggs) writes: [If this isn't in the Frequently Asked Questions file it should be] >When I installed [a] new [diskette] drive, I wanted it to be the A: drive so >I removed my old A: drive, left the old B: drive in place, and installed >the new 1.44M drive as A:. When I booted the system, the new A: worked >fine but the old B: kept giving me a "not ready" error. When installing a high-density 5-1/4" diskette drive, or a 3-1/2" drive, in a system with a low-density (360kbyte) 5-1/4" diskette drive, pin 34 of the low-density 5-1/4" diskette drive must be disconnected from the controller cable. Some drives have a jumper (sometimes a soldered-in wire) which can be removed to accomplish this. I've achieved the desired result by merely putting a small sliver of Scotch Brand (tm 3M :-) Transparent Adhesive Tape on the edge card connector, covering the metallic contact for "pin" 34. kEITHe /