Trigger; Trigger; S Ettin G S; Procedure Steps - Tektronix 2205 Service Manual

Adjustment Procedure—2205 Service
Equipment Required (See Table 4-1):
Leveled Sine-Wave Generator (Item 2)
5 0 - 0 Coaxial Cale (Item 6)
Dual-Input Coupler (Item 7)
INITIAL CONTROL SETTINGS
Vertical
POSITION (both)
MODE
VOLTS/DIV (both)
VOLTS/DIV Variable (both)
AC-GND-DC (both)
Horizontal
POSITION
MAG
SEC/DIV
SEC/DIV Variable

Trigger

SLOPE
LEVEL
MODE
SOURCE

PROCEDURE STEPS

1. Adjust Trigger Offset Ba!ance(R338)
a. Set the Channel 1 trace and the Channel 2
trace to the center horizontal graticule line using the
Channel 1 and Channel 2 POSITION controls.

TRIGGER

See
ADJUSTMENT LOCATIONS 1
at the back of this manual for adjustment locations.
Midrange
BOTH, NORM
and ALT
50 mV
Gal detent
DC
Midrange
XI
2 ns
CAL detent
Positive (_/" )
Midrange
P-P AUTO
CH 2
5 0 -0 Termination (Item 8)
Alignment Too! (Item 11)
b. Connect the digital voltmeter low lead to
chassis ground and the high (volts) lead to TP350
(base of Q410).
c. CHECK— The offset voltage reading is less than
100 mV. Note the reading for use in part e.
d. Set the Trigger SOURCE switch to CH 1.
e. ADJUST—Trig Offset Bal (R338) so that the
voltage reading is the same as that obtained in
part c.
f. Set the Trigger SOURCE switch to CH 2.
g. Repeat parts c through f until there is 1 mV or
less difference in the voltmeter readings between
the CH 1 and CH 2 positions of the Trigger SOURCE
switch.
h. Disconnect the test equipment from the
instrument.
2. Adjust Trigger Sensitivity (R489)
a. Set:
Vertical MODE
CH 1 VOLTS/DIV
AC-GND-DC (both)
SEC/DIV
Trigger SOURCE
b. Connect the leveled sine-wave generator out­
put via a 5 0 -fl cable and a 5 0 -0 termination to the
CH 1 X input connector.
or
c. Set the generator to produce a 50-kHz,
2.2-division display.
CH 1
0.1 V
AC
10 |iS
VERT MODE