Tektronix 2A63 Instrument Reference Book page 14

DEMO
Jerry Racanelli (Union) points out that there are
some traps
to
avoid in demoing the Type 63 in the
560 or 561. A few new and unusual design features
in these instruments, plus some old familiar traps
await the field engineer who hasn'tthoroughlyfam-
iliarized himself with the instruments before the
demo.
1. The low rep-rate on the 560/561 calibrator
provides a much wider pulse (8.3 msec) than
the more familiar (500µsec) cal waveform--
meaning much more tilt with AC-coupling.
2. The calibrator being driven by60 cycles means
that any pickup in test leads between Cal Out
and Vert input will be locked into a calibrator
display, distorting the waveform badly.
3. The AC-stabilized feature of the Type 63 pro-
vides different coupling time constants in the
l-2-5-10-20mv/cm settings where it is in the
circuit.
4. ·The DC balance control in the Type 63 is a 10
turn pot--a planetary-drive job, for easy ad-
justment, but which feels a little like a normal
pot that has slipped its moorings.
So here's the good word from Jerry:
A. Use a shielded lead (P52 cable or probe), not
a red patch cord, to demo the high-sensitivity
ranges of the 63. Otherwise, you'll see some-
thing like Fig. 1.
TEK 2A63 IRB
1-25-64
'
-
-
~"""-
_,.,._
'-.
-
I
~ ,J
w·
~ V'
-
Fig. 1. 561 with Type 63.
1 MV/DIV, AC Stabilized,
input via red patch lead.
FEN 6-16-61
,...
-
"