Скачать или смотреть 🇬🇧 Amstrad ACL-386SX: Part 3 (PSU Repair & Booting) [

Let's get the power supply repaired & working again and try booting. The stock machine came with a 120MB hard drive (type 40) but this one has been upgraded with a 541MB Connor MFS541A. This drive isn't fully compatible with the BIOS, which supports a maximum of 504MB only.

The geometry of this drive is:
Cylinders = 523
Heads = 32
Sectors = 63

After some fiddling I discovered the correct BIOS settings for the drive to work:
Cylinders = 523
Heads = 16 (BIOS max.)
Sectors = 63

The next issue seems to be the floppy drive - I'll get that out next and see if I can repair it. I would also like to switch to a CF drive but I'm not sure how to do it on a 80386 machine ... I've only ever installed one with an XT-IDE interface on 8086 machines ... ?

00:00 ... Intro
00:50 ... Soldering Tunes
02:42 ... Let's test the PSU (OK!)
04:00 ... Powering on the machine
08:10 ... Checking the boot-up (video capture)
18:53 ... Removing the hard drive
22:40 ... Successful boot/exploring the hard drive
28:55 ... Memory module connector
30:10 ... Channel thanks & outro

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From Part 2:
Let's strip down the Rubycon RPS-1205 power supply and check for leaks ... oh, there's actually quite a few failed electrolytic capacitors! I'm guessing it was powered on to test after a few decades which triggered the capacitors to fail.

I'll have to order replacements - I want to make sure I get good quality ones with the right pin pitch.

I'll also clean and reapply fresh thermal paste to all the transistors with heat sinks.
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From Part 1:
A big thank you to Steve at the base of the Blue Mountains, west of Sydney, for sending me this weighty (8.15kg!) Amstrad ACL-386SX120 laptop from 1991! Really appreciate it!

Unfortunately it doesn't seem to work - the Rubycon RPS-1205 power supply spins up the fan but doesn't seem to output anything over 1VDC to the motherboard (yes, even "under load" when connected to the motherboard). So some work is required.

There is some excellent documentation here, including stripping the power supply - maybe that's what I need to do:
https://forum.vcfed.org/index.php?thr...

This machine has the following features:
80386SX at 20MHz
80387 co-processor installed
DOS 5.0 and Windows 3.0 (on ten disks originally)
max. 20MB of RAM installed (4MB of built-in RAM plus 16MB expansion)
120MB swappable hard drive
3½" floppy drive with 36-pin Centronics for external drive
colour, backlit TFT LCD screen
built-in VGA/EGA/CGA/MDA/Hercules support & DE15 for external monitor
5-pin DIN socket for external keyboard
built-in trackball & buttons
serial (DE9) and parallel (DB25) ports
one AT expansion slot

The 386SX has a 24 bit address bus and is thus apparently limited to being able to address up to 16MB ... but the manual definitely says that up to 20MB can be installed and configured ... let's see ...
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Music by Karl Casey @ White Bat Audio
https://karlcasey.bandcamp.com
   / @whitebataudio