Solution:

The below table is the test result for PCM-4862 with different 486 CPUs . The test target boards are from customer , S/N is S8L010030849 and S8901528. It seems that the high speed CPU (3.3V) would be stable on PCA-4862 . I also found if disable external cache then no fail occurred on PCM-4865 with any kind of 486 CPU . 45~60C 60C+ Intel DX-33 (5v) Fail Pass Intel DX2-66 (5v) Fail Pass Cyrix DX2-80 (5v) Fail Pass AMD DX4-100 (3.3v) Pass Pass AMD 5x86-133 (3.3v) Pass Pass notes: Fail means that can not boot up from floppy driver . Problem: PCM-4862 would fail at 45C when using DX2-66 CPU Solution: To remove C42 ,C43 . See the below chart.