Power Supply And Crt Display; Initial Control Settings; Procedure Steps; Check/Adjust Power Supply Dc Levels - Tektronix 2205 Service Manual

Adjustment Procedure—2205 Service

POWER SUPPLY AND CRT DISPLAY

Equipment Required (See Table 4-1):
Leveled Sine-Wave Generator (item 2)
Time-Mark Generator (llsrn 3)
Digital Voltmeter (Item 5)
See

INITIAL CONTROL SETTINGS

INTENSITY
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

t. Check/Adjust Power Supply DC Levels (R916)
NOTE
Review the information at the beginning of
the Adjustment Procedure before starting this
step.
5 -4
■'AOJUSTMI^
at the back of this manual for adjustment locations.
Visible display
Midrange
CH 1, NORM
10 mV
CAL detent
GND
Midrange
XI
X-Y (fully
ccw)
CAL detent
Positive (-/" )
Midrange
P-P AUTO
EXT. EXT
50- f t Coaxial Cable (Item 6)
50- f t Termination (Item 8)
Alignment Tool (Item 11)
a n d a d ju s tm e n t lD c a tio n s 2
a. Connect the digital voltmeter low lead to
chassis ground and connect the volts lead to the
-8 .6 V, supply (W989).
b. CHECK—Voltmeter reading is -8 .5 V to
-8 .7 V. If the reading is within these limits, skip to
part d.
c. ADJUST—The -8.6 V, Adj potentiometer
(R916) for a voltmeter reading of -8 .6 V.
d. CHECK—Voltage levels of the remaining power
supplies listed in Table 5-2 are within the specified
limits.
e. Disconnect the test equipment from the
instrument.
Table 5-2
Power Supply Limits
Power Test
Point
Supply
-8 .6 V,
W989
+5.0 V,
W991
+8.6 V, W987
W984
+102.0 V
+205.0 V W985
+22 V unreg W752
2. Adjust CRT Grid Bias (R851)
a. Adjust the front-panel FOCUS control to pro­
duce a well-defined dot.
Reading
(Volts)
-8.56 to -8.64
+4.85 to +5.15
+8.34 to +8.86
+98.9 to +105.0
+198.8 to +211.1
Approx. +24 V