Replacing the HDD
In case of a malfunction, the original hard disk can be exchanged for a Compact Flash card. Make sure that the replacement card supports the ability to be used as a "fixed disk". Usually these are called "industrial grade" cards.
"Consumer grade" CF cards are usually detected as "removable drives" and won't work in the scope. Since the scope supports FAT16, the maximum partition size is roughly 4GB.
A PCMCIA to CF card adapter can be used to convert the PCMCIA style HDD option to CF card.
A standard 2Gb Transcend TS2GCF133 card and 4Gb Transcend TS4GCF133 card have been verified to work in both the 2.5" HDD and PCMCIA versions of the HD option.
Replacing the FDD with a USB drive
The internal FDD drive can be replaced with a GOTEK Floppy Emulator. The conversion is described on the TDS420 page.