Now that the Front Panel is working, I need to fix the SIO card which I think accidentally destroyed during the troubleshooting of the Front Panel. SIO card received 9V instead of 5V now all LEDs are on and no response from the board. So I am guessingthat I fried the 74LS259 bit latch which has a max Vcc 5.5 unlike the 74HC, and directly connected to the LEDs. Next would be to replace 74LS01, however I only have a 74LS03 that won’t work.?
Kerem Kapkin