Hi,

I am enjoying this thread a lot.

One nice feature of the 7603 is that you can substitute
a "delaying" or "delayed" sweep plug-in (7B80 or 7B85),
normally used in a 7804 400MHz four-slot instrument,
for the 7B53 normally found in a 7603.

I tried this once in an emergency, and tended to leave
the 7B80 in the 7603 afterwards.
The triggering seems a bit more stable using
a 7B80 or 7B85, and usually I don't need a dual time base.

73,
Ed Knobloch