Commodore 128D disk drive problems
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From: Murple on 16 Mar 2007 00:45 I have a Commodore 128D-CR that works fine, with the exception of the disk drive. It worked fine when I first got it (eBay) and for a few weeks after. Then all of the sudden, it began being unable to read most disks. Some disks it can still read, but I'd say 9 out of 10 disks it can't even pull up a directory, and on the ones where it can get a directory, it often cant load programs. I've opened the case, and the drive heads seem to move OK, though I dont know what the movements to look for are so it could be going to the wrong positions. The heads looked clean, but I did air-dust the drive and cleaned the drive heads too, just in case. I read Ray Carlson's 1541 troubleshooting FAQ off the web and tried to do a disk initialization which can fix a confused drive. The head seemed to move, but then I'd get a READY. prompt without any error printing on screen first, but the LED on the drive would be flashing. I tried to format a disk, another recommended step. It tells me I have a bad disk. I also tried formatting a disk using an Action Replay since I saw a post on here that some people were able to format in 128D's with an AR but not without, due to some different logic paths when the cartridge DOS routines are used vs. BASIC. I get drive not ready errors, so, I suppose I have a different problem than that poster had. I would suspect alignment, but usually a misaligned drive can read disks it formats, but not disks from other drives. At least that's what I gather based on things I've read in the past and personal experience with misaligned 1541s. This can't even format a floppy which I know isn't bad (the disk isn't bad, I mean... I can format it in my 1541). Note I get a bad disk error formatting in BASIC, and drive not ready with Action Replay's format. My electronics skills are limited, so... anyone have any ideas of things to check, explainable in the simplest possible way? I have a multimeter around somewhere, but no fancy test equipment. I also have no other 128D's or 1571's to swap parts out with. I'd really like to get this thing working since its a cool computer.
From: Tom Lake on 16 Mar 2007 01:41 > My electronics skills are limited, so... anyone have any ideas of > things to check, explainable in the simplest possible way? I have a > multimeter around somewhere, but no fancy test equipment. > > I also have no other 128D's or 1571's to swap parts out with. I'd > really like to get this thing working since its a cool computer. Unless you're doing it as an exercise in debugging, just get a 1571 drive off eBay for about $15.00 and replace the internal drive in the 128DCR. I did that for one of mine and I'm no hardware genius. It's simple plug in. No soldering or modifications needed. Just make sure to keep track of which cable goes where and the orientation. They're not keyed. Tom Lake
From: Mangelore on 16 Mar 2007 02:43 Take a close look at the front of the drive where the lever pushes down on the head lifting arm. There should be a small square plastic film stuck down like a sticker. With time this moves out of place. As a result, the drive head doesn't go down close enough to make contact the disk. I once moved this into place and the drive worked again. It's worth a shot. Good luck
From: Rick Youngman on 16 Mar 2007 03:03 On Mar 15, 11:43 pm, Mangelore <fot...(a)commodore128.org> wrote: > Take a close look at the front of the drive where the lever pushes down > on the head lifting arm. There should be a small square plastic film > stuck down like a sticker. With time this moves out of place. As a > result, the drive head doesn't go down close enough to make contact the > disk. I once moved this into place and the drive worked again. It's > worth a shot. Good luck Had the same problem with one of mine, but in my case, the lever itself had moved a bit on the shaft due to wear ( and Sysop Disk-Swap Abuse at 3 AM ).. so what felt like it was "locking down" was indeed far from the truth. Reeko
From: a7yvm109gf5d1 on 16 Mar 2007 08:45
How did you clean the heads? |