UNIDENTIFIED
TURBO MAINBOARD
| Processor | 8088 | 
| Processor Speed | 4.77/8MHz | 
| Chip Set | Unidentified | 
| Video Chip Set | None | 
| Maximum Onboard Memory | 640KB | 
| Maximum Video Memory | None | 
| Cache | None | 
| BIOS | Unidentified | 
| Dimensions | 330mm x 218mm | 
| I/O Options | None | 
| NPU Options | 8087 | 
 
| CONNECTIONS | |||
| Purpose | Location | Purpose | Location | 
| Operating mode interface | P3 | Keyboard connector | P5 | 
| Speaker | P4 | Reset switch | SW2 | 
| USER CONFIGURABLE SETTINGS | |||
| Function | Label | Position | |
| I/O address is C0H (bit 0 low = turbo mode; high = normal mode) | E1 | Pins 1 & 2 closed | |
| I/O address is 061H (bit 2 low = turbo mode; high = normal mode) | E1 | Pins 2 & 3 closed | |
| CPU changes speed during disk drive access | E6 | Closed | |
| CPU does not change speed during disk drive access | E6 | Open | |
| Boot memory test enabled | SW1/1 | On | |
| Boot memory test disabled | SW1/1 | Off | |
| NPU not installed | SW1/2 | On | |
| NPU installed | SW1/2 | Off | |
| DRAM CONFIGURATION | ||||
| Size | Bank 0 | Bank 1 | Bank 2 | Bank 3 | 
| 64KB | (9) 4164 | None | None | None | 
| 128KB | (9) 4164 | (9) 4164 | None | None | 
| 192KB | (9) 4164 | (9) 4164 | (9) 4164 | None | 
| 256KB | (9) 4164 | (9) 4164 | (9) 4164 | (9) 4164 | 
| 256KB | (9) 41256 | None | None | None | 
| 512KB | (9) 41256 | (9) 41256 | None | None | 
| 576KB | (9) 41256 | (9) 41256 | (9) 4164 | None | 
| 640KB | (9) 41256 | (9) 41256 | (9) 4164 | (9) 4164 | 
| DRAM JUMPER/SWITCH CONFIGURATION | |||
| Size | E4 | SW1/3 | SW1/4 | 
| 64KB | Open | On | On | 
| 128KB | Open | Off | On | 
| 192KB | Open | On | Off | 
| 256KB | Open | Off | Off | 
| 256KB | Closed | On | On | 
| 512KB | Closed | Off | On | 
| 576KB | Closed | On | Off | 
| 640KB | Closed | Off | Off | 
| FLOPPY DRIVE SELECTION | ||
| Drives installed | SW1/7 | SW1/8 | 
| 1 | On | On | 
| 2 | On | Off | 
| 3 | Off | On | 
| 4 | Off | Off | 
| MONITOR SELECTION | ||
| Type | SW1/5 | SW1/6 | 
| None | On | On | 
| Color (80 x 25) | On | Off | 
| Color (40 x 25) | Off | On | 
| Monochrome | Off | Off | 
| ROM SELECTION | |||
| U25 address | U26 address | E2 | E3 | 
| F6000H - FDFFFH | FE000H - FFFFFH | Closed | Closed | 
| F4000H - FBFFFH | FC0000H - FFFFFH | Closed | Open | 
| F0000H - F7FFFH | F8000H - FFFFFH | Open | Open |