Good day ! First, I'm showing off a little: I finally assembled Kh8088, which had been working for a long time, into a case. For some reason, I love 19" cases))) In the photo: Xi8088 by skiselev, CGA Redux by hkzlab, OPL2 and FDC by skiselev, VCF XT-IDE Rev 2 and ISA Backplane by Alexandru Groza. …

Thanks to Tronix for the tip. The solution to the problem turned out to be exactly as he described. Replacing several microcircuits with 74S (K531) helped, the board works flawlessly. All the same, I don't understand why it didn't work when I replaced the same microcircuits with 74F (K1531)...

And yes, I also tried different types of IC in some of seemed to me important sections of the circuit until I achieved a result. I tried to follow a simple rule - install those series of IC that are indicated in the original scheme on the github, that is, all the main chips of the 74LS (K555) …

About the demandingness of CGA Redux to the types of chips used. I couldn't even think that in some schematics there could be a situation that the microcircuits used would turn out to be too fast! Because, usually, the opposite happens - you have to look for the fastest possible ones. And that is …

Good evening ! I also suspect that the problems with my CGA Redux card lie somewhere in the /RAS, /CAS, or /WE signal generation. The fact that you had an almost similar situation only strengthened my suspicions. Because I was still not sure about the control signals of the address registers /EN_CPU …

Good day ! My board is also almost entirely built on Soviet microcircuits (90% -1533, 5% - 555, 5% - 74LS, RAM - РУ5Д). So I will definitely try your method. As soon as I have free time. Thank you in advance !

Good evening ! Forced to ask for help, I am no longer able to solve the problem on my own. So, CGA Redux card is assembled and even launched by me. However, in the 486DX motherboard it does not start at all; in a set with 386SBMC by Alexandru Groza starts, but quickly "hangs"; in a set with Xi8088 …