TANDY/RADIO SHACK
4025 LX (250-5125), 4033 LX
| Processor | 80386 | 
| Processor Speed | 25MHz | 
| Chip Set | Unidentified | 
| Video Chip Set | None | 
| Maximum Onboard Memory | 16MB (on external memory cards) | 
| Maximum Video Memory | None | 
| Cache | 32KB | 
| BIOS | Unidentified | 
| Dimensions | 355mm x 304mm | 
| I/O Options | External memory cards (2) CPU slot, floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial port | 
| NPU Options | 80387/3167 | 
 
| CONNECTIONS | |||
| Purpose | Location | Purpose | Location | 
| PS/2 mouse port | CN1 | External battery | CN6 | 
| Serial port | CN2 | Speaker | CN7 | 
| Parallel port | CN3 | External memory cards | SL1 & SL2 | 
| IDE interface | CN4 | CPU slot | SL3 | 
| Floppy drive interface | CN5 | ||
| USER CONFIGURABLE SETTINGS | |||
| Function | Label | Position | |
| » | Monitor type select through software | J1 | Pins 2 & 3 closed | 
| Monitor type select color | J1 | Pins 1 & 2 closed | |
| Monitor type select monochrome | J1 | Open | |
| » | IDE IOCHRDY enabled | J4 | Closed | 
| IDE IOCHRDY disabled | J4 | Open | |
| » | IDE DIAG normal operation | J5 | Open | 
| IDE DIAG diagnostic mode | J5 | Closed | |
| » | I/O recovery mode enabled | J6 | Closed | 
| I/O recovery mode disabled | J6 | Open | |
| » | Factory configured - do not alter | J7 | Closed | 
| » | Factory configured - do not alter | J8 | Closed | 
| » | Factory configured - do not alter | J9 | Closed | 
| DRAM CONFIGURATION | ||||
| Size | Bank 0 | Bank 1 | Bank 2 | Bank 3 | 
| 1MB | (4) 256K x 9 | None | None | None | 
| 2MB | (4) 256K x 9 | (4) 256K x 9 | None | None | 
| 4MB | (4) 1M x 9 | None | None | None | 
| 8MB | (4) 1M x 9 | (4) 1M x 9 | None | None | 
| 4MB | (4) 256K x 9 | (4) 256K x 9 | (4) 256K x 9 | (4) 256K x 9 | 
| 10MB | (4) 1M x 9 | (4) 1M x 9 | (4) 256K x 9 | (4) 256K x 9 | 
| 16MB | (4) 1M x 9 | (4) 1M x 9 | (4) 1M x 9 | (4) 1M x 9 | 
| Note: Banks 0 & 1 are located on the first memory card and banks 2 & 3 are located on the second memory card. | ||||
| CACHE CONFIGURATION | 
| Note: The location of the 32KB cache is unidentified. | 
| BIOS SELECTION | |||
| Setting | J2 | J3 | |
| 27128 | Open | Open | |
| » | 27256 | Closed | Closed | 
| 27512 | Open | Closed | |
| MISCELLANEOUS TECHNICAL NOTE | 
| Jumpers are labeled for information and location purposes only. The purpose of SL4 is unidentified. |