I got few blank chips of intel P87C521 DIP40 c1980 and wanted to copy an original one same part number. The programmer BEEPROG+ reads the original ok which is not code protected but when I insert the blank one it gives me error while programming. I tried 3 different ones with same error message. The device list in the programmer has only AMD 87C521 not intel. Could this be the problem? I couldn't find datasheet for intel P87C521 anywhere, there is intel P87C52-1 which might not be the same. Any ideas?
Mahmood