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.  |