SENSATION!  (250-1651)        Upgrade Processor        Faxback Doc. # 2734

Installing an Upgrade Processor

The performance upgrade socket on the main logic board enables you to
quickly install a new processor for a marked increase in performance.

Note:  The table in the following procedure summarizes
       the benefits of installing an upgrade processor.

Before beginning the installation, turn off the computer and disconnect
all cables.  Discharge any accumulated static electricity from your body
by touching a grounded metal object.  Open the computer.  Remove any
adapters installed in the expansion slots.  If you are installing an i486
DX or an i486 DX2, you must install an Intel-approved heat sink with the
processor.  The i486 DX4 upgrade processors come with an approved heat sink
installed.

Follow these steps to install an upgrade processor:

1. Open the performance upgrade socket by lifting the
   handle to the fully vertical position:

2. Remove the existing processor chip.

3. Position the processor so that its notched corner aligns
   with the socket's notched corner.

DO NOT ATTEMPT TO REMOVE THE i486 SX PROCESSOR IF IT IS SOLDERED TO THE
MAIN LOGIC BOARD.  The computer automatically stops accessing the i486 SX
processor when an OverDrive processor is installed.

4. Taking care not to bend or touch the metal pins, insert
   the processor into the socket by lowering the handle
   until it locks into place.

Install jumpers as listed in the following table:

┌─────────────────┬───────────────────────────┬───────────────────────┐
│Installing this  │Provides these benefits    │And requires           │
│upgrade          │                           │these jumper           │
│processor        │                           │changes                │
├─────────────────┼───────────────────────────┼───────────────────────┤
│     i487 SX     │Enhances mathematical      │Jumper W6 pins 1-2.    │
│      math       │processing for math-       │Jumper W7 pins 1-2.    │
│   coprocessor   │intensive programs.        │                       │
├─────────────────┼───────────────────────────┼───────────────────────┤
│     i486 DX     │Adds math coprocessor      │Jumper W6 pins 1-2.    │
│                 │                           │Jumper W7 pins 1-2.    │
├─────────────────┼───────────────────────────┼───────────────────────┤
│  i486 DX2 ODP   │Adds math coprocessor      │Jumper W6 pins 2-3*.   │
│   "OverDrive"   │functionality and doubles  │Jumper W7 pins 1-2.    │
│                 │the speed of the CPU clock │                       │
│     50 MHz      │  ---------------------->  │Jumper W1 pins 1-2*.   │
│     66 MHz      │  ---------------------->  │Jumper W1 parked.      │
├─────────────────┼───────────────────────────┼───────────────────────┤
│  i486 DX4 ODP   │Adds math coprocessor      │Jumper W6 pins 2-3*.   │
│   "OverDrive"   │functionality and triples  │Jumper W7 pins 1-2.    │
│                 │the speed of the CPU clock │                       │
│     75 MHz      │  ---------------------->  │Jumper W1 pins 1-2*.   │
│    100 MHz      │  ---------------------->  │Jumper W1 parked.      │
├─────────────────┼───────────────────────────┼───────────────────────┤
│  i486 DX2 ODPR  │Adds math coprocessor      │Jumper W6 pins 1-2.    │
│   "OverDrive"   │functionality and doubles  │Jumper W7 pins 1-2.    │
│   (Retrofit)    │the speed of the CPU clock │                       │
│     50 MHz      │  ---------------------->  │Jumper W1 pins 1-2*.   │
│     66 MHz      │  ---------------------->  │Jumper W1 parked.      │
├─────────────────┼───────────────────────────┼───────────────────────┤
│  i486 DX4 ODPR  │Adds math coprocessor      │Jumper W6 pins 1-2.    │
│   "OverDrive"   │functionality and triples  │Jumper W7 pins 1-2.    │
│   (Retrofit)    │the speed of the CPU clock │                       │
│     75 MHz      │  ---------------------->  │Jumper W1 pins 1-2*.   │
│    100 MHz      │  ---------------------->  │Jumper W1 parked.      │
├─────────────────┴───────────────────────────┴───────────────────────┤
│ *Indicates default setting                                          │
│**Note: This machine will not accept the Pentium Overdrive Upgrade   │
│  Processor.  It does not have the required 238 pin upgrade socket.  │
└─────────────────────────────────────────────────────────────────────┘

5.  Replace any expansion adapters you removed, close the
    computer, and reconnect all cables.  Refer to the
    "Getting Started" section and "Closing the Computer."

(smc/BKL-04/08/96)