647

The Tektronix 647A is a 100MHz scope that is designed to operate in a wide range of temperatures. It takes two plug-ins, one for vertical, one for horizontal/sweep. It uses 10-series and 11-series plug-ins. The plug-ins resemble those that go in a 560-series scope, like the 3A3 and 3B2 plug-ins, but they are quite different are not at all compatible. The 647A contains vertical and horizontal amplifiers, whereas in the 560-series, the plug-ins drive the deflection plates directly. The 647A followed the Type 647, which is similar but has 50MHz bandwidth. There is also an RM647A.

Is it the only scope to use those plug-ins? It is unusual to see only one scope in what appears to be the beginning of a series. Was it discontinued because of lack of demand? What replaced it?