Although the SD1 is an older instrument I still reguarly have these in for upgrades and maintenance including fitting the USB/SD upgrades which is by far the most valuable update for any older Solton/Ketron instrument.

Fitting is a little tricky and requires some skills but no soldering. If you are able to work methodically and no how to handle static sensitive devices you should be ok to fit. It isnot just a matter of unplugging the floppy disk and connecting the reader.If you are concerned you should not attempt the job and ask an engineer to undertake the task. Here in the UK we have fitting service.

If you purchase a used Hard drive, i would suggest to keep it below 20gb. When you instal the hard drive it will automatically format. However it will then be blank. You will need a host cable and copy files manually from a computer to the hard drive via the host port. (idealy you need an old computer with a serial port running no later then Windows XP). The data from the old hard drive can be retrieved using the disk to fat converter available on the Ketron website. it will read but not write data.

The SD1's last update was 6.0A and is only for use with instruments fitted with the USB/SD reader whilst 4.0B is the last version for a standard SD1. There are always people who do not like change or get used to a particular 'sound' (remember the CD vs vinyl discussions?). Wether you prefer the revised sound engine is a matter of choice.

You could try downloading the styles from ketrons library - you may have to do some work to make them sound correct. I found when converting X series styles to the SD7 i had to change some drum kits and the lower organ voice was always one octave lower.