The 7B71 is a single time base, which can be used as-is, or to provide a
delayed trigger to a second time base plugged into another hole. When
one timebase is used to delay another, it allows seeing an expanded-time
closeup of a part of a waveform.

The 7B53A is a dual timebase -- two timebases in the same package. One
can be used to delay the other, so you can do the whole thing with the
one plugin.

Roy Lewallen, W7EL

JimL wrote:
I need to buy a time base plug-in for my Tek 7704 mainframe.

The7B53A is described as being a "Delayed/delaying time base in one", while
the 7B71 is a" Delaying time base".

Can someone tell me the difference? Tnx, Jim.