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

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:

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.

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.