HP-85 Belts needed

The DC-100 cartridges are not preformatted, and will work in the HP-85, 9815, 9825, etc. The 9144 (and 9145) require a preformatted DC-600 style cartridge. The 9142 can format a blank DC-600 cartridge, but the format is not compatible with the 9144/9145. One caveat on buying used DC-100 tapes: when the tapes are stored for a long time and not regularly wound and rewound, the "rubber band" inside the cartridge (that actually moves the tape) can damage the oxide and cause it to lift from the tape backing. Usually the oxide comes off the BOT area of the cartridge, and not only does this remove the directory area, but the now transparent area of the tape confuses the EOT sensors and makes the tape totally unusable. Probably 90% or more of the HP-85 and HP 9825 tapes I've found at swap meets are damaged in this manner. Even tapes that have never been used and are still shrink wrapped may be damaged in this way if they're old enough.

from DC-100 to DC-2120 and beyond - is spooled such that the oxide face is