Table of Contents

Packard 386 SBC board

This is the processor board from a Packard 500TR flow scintillation analyser. My board came from the unit in DextersTechLab's teardown video.

It's essentially an ISA-bus 386 PC on an ISA card.

Part numbers on the PCB:

Features:

Backup battery

The standard backup battery is a 3.6V lithium thionyl chloride cell.

Unfortunately a 3V coin cell is not suitable: the board has a very high discharge current. Three AA NiMH or alkaline cells may be a better replacement.

Connectors and jumpers

J1 - Watchdog

3-pin 0.1in-pitch header

Pins from left to right, with the RAM slots held at the left.

1 2 3
notch
1
2 MAX891 pin 11 (Watchdog In)
3 0V

This is likely a reset switch input.

J2 - PS/2 Mouse

5-pin 0.1in-pitch header

Pins from left to right, with the RAM slots held at the left.

1 2 3 4 5
notch
1 Mouse Data (82C710 pin 61)
2
3 0V
4 5V via fuse
5 Mouse Clock (82C710 pin 60)

J3 - Keyboard

10-pin IDC connector

Pins from left to right, with the RAM slots held at the left.

1 3 5 7 9
2 4 6 8 10
notch
1 Keyboard Data
2 Keyboard Clock
3 0V
4
5 5V
6
7
8
9
10

J4 - Front Panel

Mounted flat to the PCB. 8-pin (4×2) 0.1in-pitch Dupont connector.

Pins from left to right, with the RAM slots held at the left.

PCB
1 3 5 7
2 4 6 8
1 Power LED + – via 150R to +5V
2 Power LED - – to 0V
3 Keylock switch 0V
4 Keylock, connect to 0V to lock – to 8042 pin 34
5 Hard drive LED + – via 200R to +5V
6 Hard drive LED -
7 PC Speaker – via fuse to +5V
8 PC Speaker – via 33R to drive circuit

Jumpers