π¬π§ Husky Hunter: Part 3 (New External Keyboard) [TCE #0562]
22Thanks to #PCBWAY for their ongoing support ... www.pcbway.com
Let's try out the "external" keyboard I designed to replace my Hunter's built-in keyboard (faulty due to corrosion in the keyboard membrane).
The keyboard does indeed work correctly ... but, it seems that there are some issues with my Hunter that cause it to start misbehaving after a few minutes. I did note that there is corrosion still evident on some parts of the boards ... I have not yet given any boards a wash, just replaced obviously damaged parts earlier.
The keyboard design can be found here - as of 18-Jan-2025, still "under test" in my opinion:
https://github.com/0ddjob/Husky_Computers
00:00 ... Intro
00:09 ... PCBWAY segment
01:30 ... Replacement keyboard
04:40 ... Testing
07:26 ... Keyboard close-up
08:38 ... Misbehaving Husky
09:13 ... Corrosion on components
09:52 ... Channel thanks & outro
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From Part 2:
As they keyboard membrane was knackered, I'm attempting to build a replacement keyboard so I can try the machine. For now I'm just using tactile switches on some prototyping board but as I've also drawn the schematic ... hopefully correctly ... in Kicad, I could also create a more professional-looking keyboard using proper key switches:
https://github.com/0ddjob/Husky_Computers
I was planning to just use the machine in another case but I get the feeling you would like it back in its original case ... so a replacement membrane will need to be designed and created eventually.
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From Part 1:
Let's take a look at this marvel of British engineering from 1983, the ruggedised CP/M computer called the Husky Hunter by Husky Computers Ltd.
It comes with a massive 208KBytes of battery-backed RAM and runs a 4MHz Z80-compatible CPU, the NSC800. It uses CMOS extensively to allow it to draw a mere 10-20mA at 6V when idling. It includes some handy software in its 48KByte of ROM, including a CP/M 2.2 shell and BASIC.
Its sole means of communication is a DB25 port for V.24/RS232 serial communication.
This example of British computer engineering history was rescued from a garbage bin by Andy P. (ebay: synthpartsuk), so a big thanks to his eagle eyes.
Unfortunately it wasn't working (hence the toss I guess), so I had to dismantle it (which is what we do on this channel anyway).
Despite the big red label on the machine stating "DO NOT STORE WITHOUT BATTERIES", the usual corrosion-due-to-STORING-WITH-BATTERIES occurred - it also has an internal Varta rechargeable battery that, after 40 years, has also gone bad.
Despite the excellent design & build quality, they still made the mistake of using a delicate keyboard ribbon that crumbled after 40 years ... being near to the battery corrosion probably didn't help either.
So after a bit of cleaning, I supplied it with 6VDC to its battery terminal (negative to pin 16 of the keyboard connector) and then figured out the [ON] button pins on the keyboard connector: temporarily ground pin 17 to turn on ... i.e. pin 17 to pin 16.
And the machine booted with no issue! Looks great. The screen confirmed the ROM version: 9G60h. And the CP/M compatible O/S itself is called DEMOS.
Its days of being a ruggedised CP/M computer being thrown around in the wilds of the Scottish highlands or "run over by an Army truck" are well and truly over. I'm hoping to come up with a replacement keyboard and then re-house this fine fellow in an alternative case.
If you want to see more examples of the Husky computers, check out βͺ@TheEPROM9β¬'s channel - he has quite a few examples and videos on these machines - here's his playlist:
Β Β Β β’Β HuskyΒ ComputersΒ Β
Lots of info here:
http://huskyhunter.shedlandrobotics.co.uk/
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https://karlcasey.bandcamp.com/
Β Β Β /Β @whitebataudioΒ Β