COMPAQ COMPUTER CORPORATION
===========================

   PRESARIO 400 SERIES

   Processor    80486SX/80487SX/80486DX/ODP486SX/80486DX2         
   Processor    25/33/50(internal)/66(internal)MHz                
   Speed        
   Chip Set     Compaq                                            
   Max. Onboard 16MB                                              
   DRAM         
   Cache        None                                              
   BIOS         AMI                                               
   Dimensions   330mm x 218mm                                     
   I/O Options  Riser card, floppy drive interface, game port,    
                IDE interface, parallel port, PS/2 mouse port,    
                serial port                                       
   NPU Options  None                                              

<gopher://bitreich.org/I/th99/m/C-D/32243-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose         | Location | Purpose            | Location |
   |-----------------+----------+--------------------+----------|
   | PS/2 mouse port |   CN1    | Power LED &        |    J2    |
   |                 |          | keylock            |          |
   |-----------------+----------+--------------------+----------|
   | Serial port     |   CN2    | Floppy drive       |    J3    |
   |                 |          | interface          |          |
   |-----------------+----------+--------------------+----------|
   | Parallel port   |   CN3    | Speaker            |   J13    |
   |-----------------+----------+--------------------+----------|
   | Game port       |   CN4    | External battery   |   J16    |
   |-----------------+----------+--------------------+----------|
   | Modem ports     |   CN5    | Riser Card         |   SL1    |
   |-----------------+----------+--------------------+----------|
   | IDE interface   |    J1    |                    |          |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |             Function             | Jumper |    Position    |
   |----------------------------------+--------+----------------|
   |>> | CPU type select PGA          |   P2   |   pins 2 & 3   |
   |   |                              |        |     closed     |
   |---+------------------------------+--------+----------------|
   |   | CPU type select PQFP         |   P2   |   pins 1 & 2   |
   |   |                              |        |     closed     |
   |---+------------------------------+--------+----------------|
   |>> | CMOS memory normal operation |   P6   |      Open      |
   |---+------------------------------+--------+----------------|
   |   | CMOS memory clear            |   P6   |     Closed     |
   |---+------------------------------+--------+----------------|
   |>> | Modem ROM select internal    |   P7   |   pins 1 & 2   |
   |   |                              |        |     closed     |
   |---+------------------------------+--------+----------------|
   |   | Modem ROM select external    |   P7   |   pins 2 & 3   |
   |   |                              |        |     closed     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     DRAM CONFIGURATION                     |
   |------------------------------------------------------------|
   |       Size       |       Bank 0       |       Bank 1       |
   |------------------+--------------------+--------------------|
   |       1MB        |   (1) 256K x 36    |        NONE        |
   |------------------+--------------------+--------------------|
   |       2MB        |   (1) 256K x 36    |   (1) 256K x 36    |
   |------------------+--------------------+--------------------|
   |       2MB        |   (1) 512K x 36    |        NONE        |
   |------------------+--------------------+--------------------|
   |       3MB        |   (1) 256K x 36    |   (1) 512K x 36    |
   |------------------+--------------------+--------------------|
   |       4MB        |   (1) 512K x 36    |   (1) 512K x 36    |
   |------------------+--------------------+--------------------|
   |       4MB        |    (1) 1M x 36     |        NONE        |
   |------------------+--------------------+--------------------|
   |       5MB        |   (1) 256K x 36    |    (1) 1M x 36     |
   |------------------+--------------------+--------------------|
   |       6MB        |   (1) 512K x 36    |    (1) 1M x 36     |
   |------------------+--------------------+--------------------|
   |       8MB        |    (1) 1M x 36     |    (1) 1M x 36     |
   |------------------+--------------------+--------------------|
   |       8MB        |    (1) 2M x 36     |        NONE        |
   |------------------+--------------------+--------------------|
   |       9MB        |   (1) 256K x 36    |    (1) 2M x 36     |
   |------------------+--------------------+--------------------|
   |       10MB       |   (1) 512K x 36    |    (1) 2M x 36     |
   |------------------+--------------------+--------------------|
   |       12MB       |    (1) 1M x 36     |    (1) 2M x 36     |
   |------------------+--------------------+--------------------|
   |       16MB       |    (1) 2M x 36     |    (1) 2M x 36     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                   CPU TYPE CONFIGURATION                   |
   |------------------------------------------------------------|
   |     Type      |        P3        |     P4     |     P5     |
   |---------------+------------------+------------+------------|
   |    80486SX    |    pins 1 & 2    | pins 1 & 2 | pins 1 & 2 |
   |    (PQFP)     |      closed      |   closed   |   closed   |
   |---------------+------------------+------------+------------|
   | 80486SX (PGA) |    pins 2 & 3    | pins 2 & 3 | pins 3 & 4 |
   |               |      closed      |   closed   |   closed   |
   |---------------+------------------+------------+------------|
   |    80487SX    |    pins 1 & 2    | pins 1 & 2 | pins 2 & 3 |
   |               |      closed      |   closed   |   closed   |
   |---------------+------------------+------------+------------|
   |   ODP486SX    |    pins 1 & 2    | pins 1 & 2 | pins 2 & 3 |
   |               |      closed      |   closed   |   closed   |
   |---------------+------------------+------------+------------|
   |    80486DX    |    pins 1 & 2    | pins 1 & 2 | pins 1 & 2 |
   |               |      closed      |   closed   |   closed   |
   |---------------+------------------+------------+------------|
   |   80486DX2    |    pins 1 & 2    | pins 1 & 2 | pins 1 & 2 |
   |               |      closed      |   closed   |   closed   |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  CPU SPEED CONFIGURATION                   |
   |------------------------------------------------------------|
   |           Speed            |              P1               |
   |----------------------------+-------------------------------|
   |           25MHz            |       pins 1 & 2 closed       |
   |----------------------------+-------------------------------|
   |           33MHz            |       pins 2 & 3 closed       |
   |----------------------------+-------------------------------|
   |           50iMHz           |       pins 1 & 2 closed       |
   |----------------------------+-------------------------------|
   |           66iMHz           |       pins 2 & 3 closed       |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                MISCELLANEOUS TECHNICAL NOTE                |
   |------------------------------------------------------------|
   |               The purpose of CN6 is unknown.               |
   +------------------------------------------------------------+