Post by Cube Inc. on Mar 24, 2023 7:39:12 GMT -7
In all my years of owning many Commodore computers and peripherals, I've never owned or used a 1581 - until now. (Well, yesterday when one I bought from eBay arrived.) I bought it "as is / untested" knowing the risk, but also hoping for an opportunity to learn a little about this drive. I was not disappointed!
When it arrived, I checked it over and powered it up, and it seemed to do normal things as far as I could tell. I found a 3 1/2" floppy and decided to see if it could format it. (I didn't have any 3.5" disks formatted for the 1581.) My first couple of attempts to format a disk seemed to start, but after 4-7 tracks it would stop and error out with a READ ERROR.
It dawned on me that I was using an HD disk, and perhaps it required a DD disk like pretty much all of the 5.25" counterparts. I rummaged through all of my 3.5" disks and found a whopping two that were not HD. Unfortunately, these errored out immediately, and did not even seem to start the format. Since at this point I still did not really know if the drive actually worked, I decided to give it a good cleaning and check everything out inside.
No change at first.
However, when I had the drive apart, I tried formatting a variety of brands of HD disks, and suddenly one formatted. I copied about 2000 blocks of data onto it - no problem. I formatted another. It worked also. And another. I tried running some software off the disk that I'd just written, and it worked perfectly but it was painfully slow so I re-flashed the ROM in the drive to JiffyDOS and that was MUCH better. I put the whole thing back together and went to format another disk, only to have it fail on the first track again. Strange. I could still read the formatted disk just fine, but could not get it to format anything. I even tried re-formatting a disk that it had just successfully formatted, and it errored out on the first track again.
Strange.
i took the 1581 apart again and with the drive in pieces on the table, retried the format on the same disk that had previously failed. This time, it went perfectly, so I started the format again and began poking around, now fairly certain that there was a connection or cold solder joint that was causing this grief. Sure enough, in the middle of a format I found that pressing on the ribbon cable immediately caused it to fail with a READ ERROR. I took the cable off and de-oxit'd both connectors, and noticed one pin in roughly the middle of the ribbon that looks like it may have been crushed, which is odd because there is nothing anywhere near the middle of the cable in the drive chassis that could have caused the injury, so I suspect it may have been like that from the factory. I also re-soldered all of the ICs on the main board for good measure; there were a number of joints that I did not like there.
Now the 1581 seems to work perfectly - I formatted close to a dozen HD (1.44 MB) disks from Maxell, Sony, Fuji, Memorex, TDK, and some un-branded ones - all which seemed to format perfectly. Of course it formats them to the 800k size, not 1.44MB, but that is no matter to me.
I did some reading and it seems like there are a variety of opinions about using HD disks in 1581's, from some people who say that they've done it for years and never had any trouble to others who insist that HD disks aren't reliable because of the higher coercivity of the media. I guess I will see how I fare on this one, but there was definitely an issue with the ribbon cable that was preventing the drive from formatting disks properly, which - when moved - appears to have completely resolved the issue. I'm still going to see if I can find some more of that ribbon and make a new connector for it *just in case*, but all in all, this drive appears to be working great, and almost matches the capacity of my beloved SFD-1001's and (ex) 8250.
I've added a poll to this post to gather feedback on your experience in using High Density 3.5" floppy disks in a 1581. I'm curious to know what the local community has found in this regard.
