21xx 486DX or 486DX2 25/33 or 50/66 MHz
21xx 486DX or 486DX2 25/33 MHz or 50/66 MHz (72-Pin SIMM)
J1 Keyboard
J2 Mouse
J3 Serial Port A
J4 Serial Port B
J5 Parallel Port
J6 Display
J7 Diskette
J8 Power
J9 Hard Disk Drive
J11 Riser
J14 VESA Video feature connector
J15 Video Disable
norm. operation Pin 1-2
J16 Cache Jumper
J17 Cache Jumper
J16 and J17 must be Pin 2-3
for upgrade to 256K
J19 RAM 72-Pin Memory - Bank 3
J20 RAM 72-Pin Memory - Bank 2
J21 RAM 72-Pin Memory - Bank 1
J22 RAM 72-Pin Memory - Bank 0
Sockets can be populated in any
order
J23 Processor-type Jumper
J24 Processor-type Jumper
J25 Processor-type Jumper
J26 LED Connector Power Pin 1-2
Hard Disk Drive Pin 3-4
J27 Speaker Volume Control (WT only)
SP103 Password Bypass
SP193 Beeper Enable
U7 System ROM
U19 Cache Memory Address Module
for 128K/256K Cache
U28 Cache Memory Socket Bank 1
U29 Cache Memory Socket Bank 1
U30 Cache Memory Socket Bank 1
U31 Cache Memory Socket Bank 1
U37 Cache Memory Socket Bank 2
U38 Cache Memory Socket Bank 2
U43 Cache Memory Socket Bank 2
U44 Cache Memory Socket Bank 2
U45 486DX, 486 Math, 486DX2
486 Overdrive or Pentium®
ODP Processor
Processor Jumper Settings J23, J24 and J25
486SX System Boards
| Jxx |
486SX |
486SX/487 Math |
486SX/486 Overdrive |
486SX Pentium® ODP |
| J23 |
1, 2 |
1, 2 |
1, 2 |
1, 2 |
| J24 |
1, 2 |
1, 2 |
1, 2 |
1, 2 |
| J25 |
1, 2 |
2, 3 |
2, 3 |
2, 3 |
486DX and 486DX2 System Boards
| Jxx |
486DX |
486DX2 |
Pentium® ODP |
| J23 |
1, 2 |
1, 2 |
1, 2 |
| J24 |
1, 2 |
1, 2 |
1, 2 |
| J25 |
1, 2 |
1, 2 |
2, 3 |
If the system board has cache memory modules already installed, the
computer has 128K cache memory. Upgrade to 256K by adding memory modules as follows:
- Bank 2 Add four 28-pin modules: 32Kx8 - 25ns SRAM
- Tag Replace existing module with one 28-pin module: 32Kx8 - 20ns SRAM
If you are installing cache memory in a board with no cache memory previousely installed, install
128K or 256K as follows:
- Bank 1 Add four 28-pin modules: 32Kx8 - 25ns SRAM (for 128K or 256K).
- Bank 2 Add four 28-pin modules: 32Kx8 - 25ns SRAM (for 256K).
- Tag Add one 28-pin module: 32Kx8 - 20ns SRAM (for 256K) or 8Kx8 - 20ns SRAM (for 128K).
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