Since I own three of those really cheap ISA/PCI eBay $3 POST cards, and two of those have died/malfunctioned in the last weeks, I'm looking at the option of building my own ISA POST card. This will also be a fun project and is probably not financially smart.

Any thoughts?

Elektor 95008-1 (1995-01):
There is a nice-looking card in Elektor magazine, issue of januari 1995. This article is in Dutch, but there are other languages of the article available online. It includes a PCB layout. Biggest issue I think would be the contents of the two GAL chips and PCB costs.

It can be configured to listen on a few ports, which is useful.

PDF (Dutch): https://drive.google.com/file/d/1eD-9vkSK-2bg … iew?usp=sharing

Image (taken from the Wikipedia article on POST cards):

https://drive.google.com/open?id=1vJd_HpgvmI6 … Iq09lCBpVfvltme

https://drive.google.com/open?id=1xjYBqXNrWzk … OLhsu2CIXziqxzh

https://drive.google.com/open?id=1WLto65Smz4x … KWw2pK40qVSUUqu

Malinov version

It uses a binary-to-digital decoders, and not able to display HEX numbers (A-F), instead some figures are displayed.

Does not sound like the best option for me, but has some schematics for reference.

http://www.malinov.com/Home/sergeys-projects/isa-post-card

bbright version

This one is well documented, and has schematics and hex files for the EPROM used. Only listens on port 80.

http://bbright.tripod.com/information/postcard.htm

Misc links

minuszerodegrees page on POST cards: http://www.minuszerodegrees.net/misc/post_cards.htm