Looking for replacements for two different DIP-40 keyboard controller chips \ VOGONS

Reply 1 of 5, by maxtherabbit

Posted on 2025-06-10, 11:48

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generally all of the AMI labeled ones are interchangeable, go with rev F or later if you want ps/2 support

Reply 2 of 5, by analog_programmer

Posted on 2025-06-10, 12:03

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maxtherabbit wrote on 2025-06-10, 11:48:

generally all of the AMI labeled ones are interchangeable, go with rev F or later if you want ps/2 support

I can't find any MEGATRENDS MEGA-KB-H-WP or MEGATRENDS MEGA-KB-F-WP chips that I can order at reasonable price. I found VIA VT82C42N chip that I can order, but I'm not sure if it's 100% compatible with these MEGATRENDS MEGA-KB-F/H-WP chips.

And what about the other one for the 386SX motherboard? Here's the picture of the original KB-controller for KMX-AL25/33SX board:

The attachment AMI KB controller.jpg is no longer available

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Reply 3 of 5, by analog_programmer

Posted on 2025-06-11, 08:18

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Ok, on TRW site there are two pictures of FIC 486-GVT-2 motherboards with VIA VT82C42N KB-controller, so it must be compatible with MEGATRENDS MEGA-KB-H-WP chip. I ordered two of these VT82C42N chips (the cheapest offer on alibaba-and-the-40-thieves was for 2 pieces bundled) for about EUR 4 including shipment. I need only one of these for FIC 486-GVT-2 motherboard, but I have no idea if the second VT82C42N chip can be used as replacement for the faulty KB-controller (with the sticker "(C) 1988-1990 AMI KEYBOARD") on the 386SX board.

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Reply 4 of 5, by MikeSG

Posted on 2025-06-11, 15:36

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Winbond W83C42 are also replaceable with the AMI keyboard controllers, pin for pin, but require a 7407 (SN7407N) instead of a 74F04 or similar near the KB controller.

They're fast like the VT82C42N, which also require a 7406/7407... If on bootup it says Keyboard error, it's most likely these chips that need changing.

Reply 5 of 5, by analog_programmer

Posted on Today, 11:12

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MikeSG wrote on 2025-06-11, 15:36:

Winbond W83C42 are also replaceable with the AMI keyboard controllers, pin for pin, but require a 7407 (SN7407N) instead of a 74F04 or similar near the KB controller.

They're fast like the VT82C42N, which also require a 7406/7407... If on bootup it says Keyboard error, it's most likely these chips that need changing.

Thanks for the input, MikeSG. I don't get what you're exactly mean, but seems like in most cases Winbond W83C42 controller will not work on the 386 board. It will become clear when I got the two Winbond W83C42 controllers.

Still I'm open for KB-controllers replacement suggestions.

The word Idiot refers to a person with many ideas, especially stupid and harmful ideas.
This world goes south since everything's run by financiers and economists.
This isn't voice chat, yet some people overusing online communications talk and hear voices.

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