Sinclair Amstrad APC 386SX

Resources

Wiki There are very few online resources about this PC. It is a rebranded Amstrad 3386. It is famous for a proprietary design of the keyboard, which can’t be replaced with anything commonly available. Without a keyboard, the PC will not boot.

Internals

Motherboard

The CMOS battery is integrated into Dallas DS1287 real time clock controller chip. The integrated battery can be replaced with an external one, following these instructions. DSC_0017

Option Jumper
Mouse IRQ on 5,4,9,3 LK9-LK12
RAM size LK19-LK22 (see memory section below)
RAM speed LK23-LK24 (see memory section below)
Enable onboard HD controlled LK27
Enable onboard VGA LK28
Enable onboard mouse interface LK30
Enable onboard parallel printer port (LPT1) LK31
Enable onboard floppy disk controller LK32
Enable onboard serial interface (COM1) LK33
Enable Power On Self Test (POST) LK34
Enable expansion bus cache LK36

CPU Card

Memory

Memory can be expanded by installing different size SIMM modules.

RAM size SIMMs LK22 LK21 LK20 LK19
1MB 4 x 256kB IN IN OUT OUT
2MB 2 x 1MB + 2 x empty IN OUT OUT IN
2.5MB 2 x 256kB + 2 x 1MB OUT IN IN IN
4MB 4 x 1MB OUT IN IN OUT
8MB 2 x 4MB + 2 x empty OUT IN OUT OUT
16MB 4 x 4MB OUT OUT OUT OUT
RAM Speed LK23 LK24
80nS OUT OUT
100nS IN OUT
120nS OUT IN
150nS IN IN

ISA Interposer Card

Power Supply

Amstrad SMP-145CB

Keyboard

This is not the keyboard that originally came with this PC. It is an Amstrad PC2386 keyboard, which is compatible with 3386 systems. Please check out the Amstrad 2386 Keyboard page where the keyboard is described in details, including the communication protocol it uses.

Hard Disk Drive

45 MB Seagate ST-157A-1. The correct parameters for this drive are provided on this page.

Floppy Disk Drive

Accessory

Reassembly

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