My best guess is that you are not using Bob's Assembly mod, and that the config setting to alter their graphics is set to "true."
Check the value of line 130: assembling_graphics = value
If it's true, change it to false, save the file (make sure you save it within the zip file) and try loading the game. Or, you could just install Bob's Assembly mod, because the 2x2-sized electronics assemblers are awesome for making circuits quickly in a small footprint! I started using it recently, but I leave that ShinyBob option set to "false" because it changes the default colors of assembling machines 2 & 3 and it confuses me.