photo_2023-06-28_19-01-54.jpg I successfully replaced a 386SX-20 with a TI486SXLC2-50-G on a IBM/PŜ1 2121 model several years ago (I used an empty EEPROM socket to plug a breadboard with the power regulator). With a 33 MHz crystal the 486SXLC2 works great at 66 MHz and the 8 kb cache makes a great …

I found this thread today. It seems that I got the same kingston sx/now upgrade to make similar experiments. I replaced the 386sx with a TI486SXLC40 (5v part, it can run in a 40 MHz or 20 MHz system ,with 2x internal clock multiplier) https://lh3.googleusercontent.com/ …

Just assembled the kit and it's working like a charm on my PS/2 Model 80 using the TSR.

"if the silver part marked 143NDK1X (near the 34-pin connector) is a 14.318180 Mhz crystal and we divide that by 4 to get the most likely master clock... then it would be 3.579545 Mhz." Of course, that is making an assumption, since I can't follow the tracks directly into the 34-pin connector. The …