I have a 300SD 1982 and have the typcial tach that will suddenly die and then come back to life. I replaced the amplifier but am still having the occasional problem. I was told that the problem is poor contact between the amp and pins. I did the "put some foam in the cap" trick which helped a bit but not completely. I was wondering, why can't I coat the pins with conductive silver grease? If the problem is connection, shouldn't this help? Has anyone tried this?