Sinclair Amstrad APC 386 SX / Amstrad 3386 SX - help!

[ppieczul]

Hi,

I have a Sinclair Amstrad APC 386 SX, also known as Amstrad 3386 SX, complete main unit with original 40MB Seagate HDD.
There is practically zero documentation on the web of this machine. Does anyone have anything related to the motherboard, jumper configurations and keyboard protocol?

I don't have an original keyboard and it seems to not follow the PC keyboard, the connector is different and it has different lines on it, no clock, etc...
Without a keyboard it is impossible to boot, as the cmos expired and it stops at detecting wrong floppy configuration.

Thanks a lot
Pawel

 

[JohnElliott]

I'm guessing the keyboard is the same as the Amstrad 2386, in which case it's a proprietary system - the controller IC in the keyboard combines the functionality of the 8042 on the AT motherboard and the 8048 in the AT keyboard.

 

[ppieczul]

After some months I managed to buy the keyboard on ebay and I reverse engineered the protocol a bit.
Since I already I own the keyboard, I will not build an adapter, but maybe someone will be in need and will make use of my documentation.
Here it is: https://oldcrap.org/2019/06/27/amstrad-2386-keyboard/

Cheers
Pawel

 

[Trixter]

Great write-up and solution!

 

[JohnElliott]

Would a dump of the keyboard microcontroller ROM be any use to you?

(When setting LEDs on an IBM keyboard, the first byte of the command is 0EDh. I think I recognise that as 11101101 in your captured bitstream).