Tektronix 442, Instruction Manual

Page: 19 / 170

Operating Instructions—442 Service
( ? ) ON indicator (LED)
Lights when power is applied to the 442 and the
POWER ON/OFF button is pressed in.
POWER INPUT SELECTOR SWITCHES and DC
BALANCE CONTROLS
(Bottom of Cabinet. See Figure 2-6.)
© ON/OFF Push Button Switch
Turns instrument ON (in) and OFF (out).
Internal Graticule
Eliminates parallax. Risetime amplitude and
measurement points are marked on the left edge
of the graticule. VOLTS/DIV and SEC/DIV set­
tings are calibrated to the graticule scale
divisions.
© PROBE ADJust
Pin connector supplies internally generated
square wave of approximately 0.5 V at ap­
proximately 1 kHz for use in checking attenua­
tion factors and compensation of probes.
Z AXIS INPUT
(Rear Panel. See Figure 2-5.)
| 0 j External Z AXIS INPUT Connector
Bnc connector accepts signals from external
sources for modulating intensity of crt display.
Signals must be time-related to the display for
stability. Positive signals decrease intensity. In­
put specification at connector is 30 V peak max­
imum input and 10,000 £1 input impedance.
Figure 2-5. External Z AXIS INPUT connector on the back pane!
of the 442.
C A U T I O N
Before operating or changing settings of Power
Input Selector switches, verify that the 442 power
cord is unplugged from the power source and that
the correct value of fuse is installed for the available
power input voltage (see Table 2-3, and Figures 2-3
and 2-6).
@ 120 V/240 V (Ac Power Input Selector Switch)
Two-position, screwdriver actuated slide switch,
which can be set to allow operation from an ac
source of either 120 V or 240 V. Positions are
marked on the cabinet.
\2) HI/LO (Regulating Range Selector Switch)
Two-position, screwdriver actuated slide switch
which can be set to allow operation from one of
two ac ranges (see Table 2-2). Positions are
marked on the cabinet.
J3) CH 1 DC BAL (Channel 1 Dc Balance Control)
Screwdriver adjustment (through cabinet). When
properly adjusted, prevents trace shift when
switching between adjacent positions of channel
1 VOLTS/DIV switch.
|4 ) CH 2 DC BAL (Channel 2 Dc Balance Control)
Screwdriver adjustment (through cabinet). When
properly adjusted, prevents trace shift when
switching between adjacent positions of channel
2 VOLTS/DIV switch.
Vertical
(Front Panel. See Figure 2-7.)
)5 ) CH 1 (X) (Channel 1 or X-axis Input)
Activated when the VERT MODE CH 1 button is
pressed in. Bnc connector for the application of
external signals to the channel 1 vertical deflec­
tion system. For X-Y operation, this connector is
the horizontalJX-axis) signal input (see Note).
2 -4 REV A MAY 1980