[vcf-midatlantic] Strange Commodore 1581 floppy drive issue

[RETRO Innovations]

On 5/16/2022 10:02 AM, Russell LeChard via vcf-midatlantic wrote:
> Good Morning All. I am seeking some help from some Commodore experts with a
> Commodore 1581 floppy Disk drive.
>
> Some background:
>
> I've been an IT specialist specializing in IBM and compatible PCs since the
> early 90's. However, I started my computing journey with the TRS-80 model
> III and  Commodore 64. I fell in love with the C64, and it began my start
> in a very successful career in IT. (see attach photo of my c64 setup in
> 1986 LOL)
>
> Recently I was lucky enough to find a C64C, a C128, and a 1581 3.5 floppy
> drive online for a reasonable price. Well, I did pay a premium for the
> 1581, but I never had one back in the day and well, I treated myself..
>
> This past weekend I tested all 3 items and for the most part all worked OK.
> I was concerned the most about the 1581 working. After a delay in
> remembering the correct syntax for the C64 format disk command (open
> 15,8,15,"N0:testdisk,01": close15) - My memory isn't what it was in my
> younger days! LOL :-D), I was able to format a disk and then save a simple
> basic prg to it. However, when I try to load this basic prg (on the C64),
> it locks up the c64 and there seems to be no activity led lights and the
> 1581. I need to reboot the C64.
>
> Now, I tried the same task using the c128 and the same 1581 and floppy
> disk, I can now format, save, and load a basic prg without any issues.
> Everything seemed to work fine. My question is, are there any known
> compatibility issues between the C64C and the 1581 that the c128 fixed? I
> always thought the 1581 was compatible with the C64 and c64C? Very Strange.
> Any thoughts and advice are welcome.Thank you in advance.
>
> Take Care,
> Russell LeChard

Set up the 128 with the 1581 and boot the 128 in 64 mode.  Try the 
commands to load the file from 64 mode and see if the same issue 
exists.  If all goes well, that points to the 64C being marginal.  If it 
fails, then I'd suspect the IEC buffers on the drive.

Yes, the 1581 is backwards compatible with the 64.

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