svv@cory.Berkeley.EDU (Nobody in Particular) (01/22/88)
I just got a hand-me-down PC from my folks last month. It's a true-blue IBM PC, with 2 half height drives and a 10 meg Maynard Hard Disk. From my inpection of the insides the the PC, it seems that the hard disk controller is soldered on piggy-back style to the disk controller. Also, the BIOS chip had been replaced by a new hard disk BIOS chip. The problem: When I set it up and booted the machine, the hard disk worked fine. I breathed a sigh of relief because the PC had endured a 450 mile road trip from So. Cal. However, neither of the drives worked. When I tried to "dir" a disk, that worked fine. But copying, reading or writing files gave me a "disk drive not ready" error. I figured that the drive heads got out of alignment in the commute so I went and bought another 1/2 ht. 360k drive. When I plugged THIS one in, as soon as I booted the computer up, both drives turned on and started running (not reading anything, just running), but DOS booted up on the hard disk as usual. But the new drive gave me similar errors. I thus concluded that the controller must be screwed up, so my question is: 1) Maynard makes my hard disk BIOS chip, my hard disk, AND my controller. Can I replace the controller with a non-Maynard board and still keep every device happy? 2) Is my controller really screwed up? Is it something else? I'd greatly appreciate any leads. I'm afraid to take my PC into the shop because the diagnosis will probably cost 10 time as much as the solution. Thanks, S. Vasudevan svv@cory.berkeley.edu (415) 845 - 9354
berger@clio.las.uiuc.edu (01/25/88)
I've never seen a hard disk controller "soldered" to the standard PC
floppy disk controller; most Maynard products are pretty good. If
you can't separate the two boards, you could replace them both, and
use the same hard drive.
The very early PC's (which don't have the (B) stamped on the back)
needed a ROM BIOS upgrade to boot from hard disk. If you're booting,
chances are good that the BIOS is ok.
Check the new floppy disk drive to be sure the option jumpers are
set correctly for your machine. You might see the behavior you
mentioned if the drive isn't set up properly. If your original
floppy disk drives can't read another diskette, you can try
formatting on the same drive that you want to read from. If that
works ok, it does indicate a possible head alignment problem.
Mike Berger
Center for Advanced Study
University of Illinois
berger@clio.las.uiuc.edu
{ihnp4 | convex | pur-ee}!uiucuxc!clio!bergerwew@naucse.UUCP (Bill Wilson) (01/30/88)
Make sure that you have the resistor pack in the right drive (the A drive) and that the DMA settings are correct. Bill Wilson