Saturn:Super Prologue 21 Model SKC-3000

Super Prologue 21 is a Saturn built into a Kareoke machine with a VA0 Saturn motherboard. This page covers the SKC-3000 variant. Not other variants. Other variants are different interally but overall are the same; a Kareoke machine using Saturn as a processor.

Common failures include no power, black screen on powerup and not reading discs. Overhauling a Prologue 21 should not be taken lightly and only approached by absolute experts with a very large amount of experience.

'''There is a messy wiring harness system inside the Prologue unit with total disassembly required to access the CD-ROM drive which is a common failure point. It is recommended to take photos on your phone overdocumenting your disassembly process in order to reduce pain in reassembly. It is also recommended to unplug, from wiring harnesses, ONE card at a time for recapping and then connecting the wiring system back to the card. Rinse and repeat.'''

Main motherboard is a normal VA0 Saturn motherboard with modification to the cartridge slot; the cartridge slot is modified to accomodate the kareoke scsi card subsystem. FRAM modification can be applied. However a region free bios replacement is not recommended as the Saturn uses a unique EEPROM module compared to standard VA0-VA0.5 Saturn motherboards. Unless the Specific Kareoke BIOS EEPROM is region patched do NOT place a regular region free EEPROM in the socket.

Roland 01-HR-SE Harmony Board
Should have a Sega logo somewhere along with "SKZ-0001 835-12275".

For this card you can use through hole capacitors fine provided they're pushed downward and position strategically.



Sega DSP Board ASSY 70459323 00
Made by BOSS. Note the light capacitor damage from SMD Capacitors.



Roland 01-SE Sound Module Board
Primary Roland Sound MIDI module.



SCSI Card
SCSI Card plugs into modified VA0 Saturn board. The HDD connects to this card. On this special 'sandwhich' card is full of RAM and SCSI LSI. It is two cards connected together with a connector.

If using radial capacitors keep in mind the capacitor legs must be very carefully trimmed so the card can be closed together again.



Denon GU-2825-1 Has all the components for Saturn to interact with SCSI HDD with SCSI port connected. It also connects to the Denon RAM card.



Denon GU-2826-1
Denon Card with 4 (!) Composite video out, S-video out, two composite inputs? and a console port.



Denon NCMK-C2X
Denon card resposible for some mixing of audio and video?





Denon GU-2825-3
Seems to be the external SCSI for for the Prologue unit that connects to Commander CD-changer unit.

Notice the two fuses that could potentially blow. They're 1.6A each



Yamaha XR650
Yamaha DC Module card



Denon GU-2821-2
One of two Denon cards on the front metal plate, right behind Prologue front panel



Denon GU-2831-3
Card attached to front faceplate responsible for volume adjustments.