Most PC BIOSes write status codes to I/O port 80h during their power-on self-test (POST). These codes can provide valuable help for troubleshooting. A POST card allows you to read these codes.

Turn off system power. Insert the card in a free ISA slot. Make sure that the card is oriented correctly. The four power LEDs should be closer to the rear of the system, the seven segment LEDs closer to the front. Incorrect orientation should not damage the POST card or the system board, but is not recommended, and we will not be liable for any damage.

Turn on system power. All four power LEDs should light up. If they don’t, one or more supply voltage is not present. Note that -5V may not be available in some systems.

The POST card will display the last value written to port 80h. If the POST code display remains blank, the system BIOS is not coming up at all - something is seriously wrong with the system board. If the POST code gets stuck at a value other than 00 (successful boot), use a POST code table to find out the meaning.

Defective POST cards will be replaced free of charge for one year from purchase. Please email sales at sales@adapters.com or call 408-745-1524 for return instructions.

The POST card may not work in EISA motherboards, which sometimes use a different port address. If you need PLD equations for different address decoding, please contact Adapters.com..