UNIDENTIFIED
TURBO MAIN BOARD (426A)
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 |
Turbo switch (to turbo switch button) | JP5 | Power LED | JP9 pins 3 & 4 |
Turbo LED | JP9 pins 1 & 2 | Speaker | P4 |
USER CONFIGURABLE SETTINGS | |||
Function | Label | Position | |
» | Factory configured - do not alter | JP1 | Unidentified |
Turbo enabled | JP6 | Closed | |
Turbo disabled | JP6 | Open | |
Turbo enabled (CTRL, ALT, +) | JP7 | Closed | |
Turbo disabled (CTRL, ALT, -) | JP7 | Open | |
Keyboard lock disabled | JP8 | Closed | |
Keyboard lock enabled | JP8 | Open | |
» | Factory configured - do not alter | SW1/1 | Off |
NPU not installed | SW1/2 | On | |
NPU installed | SW1/2 | Off | |
Note: JP6 is for turbo selectable through hardware. JP7 is for turbo selectable through software. Both jumpers cannot be closed at the same time. |
DRAM CONFIGURATION | ||||
Size | Bank 0 | Bank 1 | Bank 2 | Bank 3 |
256KB (A) | (9) 4164 | (9) 4164 | (9) 4164 | (9) 4164 |
256KB (B) | (9) 41256 | None | None | None |
512KB | (9) 41256 | (9) 41256 | None | None |
640KB | (9) 41256 | (9) 41256 | (9) 4164 | (9) 4164 |
Note: The location of banks 0, 1, 2, & 3 are unidentified. |
DRAM JUMPER CONFIGURATION | ||
Size | JP3 | JP4 |
256KB (A) | Pins 1 & 3, 5 & 7 closed | Pins 2 & 4 closed |
256KB (B) | Pins 2 & 4, 6 & 8 closed | Pins 1 & 3 closed |
512KB | Pins 2 & 4, 6 & 8 closed | Pins 1 & 3 closed |
640KB | Pins 2 & 4, 6 & 8 closed | Pins 1 & 3 closed |
DRAM SWITCH CONFIGURATION | ||
Size | SW1/3 | SW1/4 |
128KB | Off | On |
192KB | On | Off |
256KB | Off | Off |
FLOPPY DRIVE SELECTION | ||
Drives installed | SW1/7 | SW1/8 |
1 | On | On |
2 | Off | On |
3 | On | Off |
4 | Off | Off |
MONITOR SELECTION | ||
Type | SW1/5 | SW1/6 |
None | On | On |
Color (40 x 20) | Off | On |
Color (80 x 25) | On | Off |
Monochrome | Off | Off |