The E-MU Proteus MPS Plus Orchestral is essentially a Proteus MPS with an additional 4MB ROM of orchestral samples (the same sample set used in the Proteus/2). This gave you 4MB of Pop/Rock instruments and 4MB of Orchestral instruments.

ROM Cards
E-MU issued a range of ROM cards for the MPS. Each card adds 100 new presets.

9070 – MPS Pop Collection
9071 – MPS Textures/Pads
9072 – PlusPower (MPS+)
9073 – General MIDI
9074 – Fresh Mix
9075 – The Best Blend

RAM Cards
60-pin 256Kbyte SRAM memory card – p/n ZM348

Technical Specifications
Keys: 61
ROM Size: 8MB
Sample Rate/Bitrate: 39kHz 16-bit
Presets: 500
Instruments: 203
Polyphony: 32 Voices
MIDI Channels: 16
Filters: No
FX: 32
MIDI Ports: 3
Audio Outs: 4
Digital Outs: No

E-MU Proteus MPS Operation Manual

This procedure destroys any presets stored in RAM.

1. Hold both Master and Preset buttons down and power on the unit.
2. Once booted up into the Diagnostics menu, turn the Data wheel knob to Initialize.
3. Press the Enter button.
4. Press Enter again to confirm.
5. Turn the unit off, wait a few seconds and turn the unit on.
6. Load the factory user presets from SysEx file.