VOGONS


First post, by Jed118

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Hello all,

Some time ago I got duped into buying a "working and tested" 386 motherboard from an incredibly disreputable seller, and what it does is it shows a keyboard error when I plug any (or no) keyboard in there. I suspect there's trace damage from a leaking battery. There's bodge wires all over the rear of the board, which were not disclosed. If I paid $20 for it, whatever, the RAM is worth that to me, but this sent me back $100.

Anyways, does anyone know where these connections go? I can figure out the gnd and VCC, but where does DATA and CLOCK go?

male_din_5_XT_AT_Connector_Keyboard.jpg

Is it as easy as connecting them directly to the Intel 8042:

http://www.brokenthorn.com/Resources/OSDev19.html

I'm not sure which pins to connect the DIN port to, or of they go elsewhere. I don't have a free known-good AT motherboard, or else I would just probe around with a multimeter. Any help is appreciated.

EDIT - hah, ChatGPT said this:

Connections:
DIN-5 Pin 1 (Clock) → 8042 Pin 39 (KBCLOCK or P24)
DIN-5 Pin 2 (Data) → 8042 Pin 40 (KBDATA or P23)
DIN-5 Pin 4 (Ground) → Motherboard Ground
DIN-5 Pin 5 (+5V) → Motherboard +5V supply

I'll try that out with direct bodges.

(EDIT EDIT - further reading suggests I need to make a pull up resistor for DATA and CLOCK. At least I know where to start now. )

Last edited by Jed118 on 2024-12-03, 20:34. Edited 1 time in total.

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Reply 1 of 2, by BitWrangler

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Just doublechecking because we've seen all kinds here. You are powering up with the keyboard already attached to test it right? AT keyboards don't like to be hot-plugged.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 2 of 2, by Jed118

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Def. the keyboard is already connected. I have also tried several keyboards and keyboard BIOSes. I get the flashing lights, so I assume CLOCK works, it must be the data line. Or not, I don't know yet, I'll have to measure the continuity.

Youtube channel- The Kombinator
What's for sale? my eBay!