Ch 2 Step Balance (R22); Ch 3 Step Balance (R141); Ch 4 Step Balance (R161); Ch 1 Mf/Lf Gain (R13) And Compensation (C L) - Tektronix 2246 1Y Service Manual

Adjustment Procedure —2246 1Y and 2246 MOD A Service
3. CH 2 Step Balance (R 22)
a. Set:
Vertical MODE
CH 2 COUPLING
b. Position trace to center of graticule.
c. ADJUST- R22 (CH 2 STEP BALANCE) so that trace
does not move vertically while switching CH 2
VOLTS/DIV switch from 10 mV to 50 mV.
4. CH 3 Step B alance (R 141)
a. Set Vertical MODE to CH 3 (CH 2 off).
b. Position trace to center of graticule.
c. ADJUST-R141 (CH 3 STEP BALANCE) so that
trace does not move vertically while switching CH 3
VOLTS/DIV switch from 0.1 V to 0.5 V.
5. CH 4 Step Balance (R 161)
a. Set Vertical MODE to CH 4 (CH 3 off).
b. Position trace to center of graticule.
c. ADJUST-R161 (CH 4 STEP BALANCE) so that
trace does not move vertically while switching CH 4
VOLTS/DIV switch from 0.1 V to 0.5 V.
6. CH 1 M F /L F Gain (R 13) and C om pensation
( C l)
a. Set:
Vertical MODE
CH 1 VOLTS/DIV
CH 1 COUPLING
SEC/DIV
b. Connect calibration generator to CH 1 inputvia50O.
BNC coaxial cable and 50 n BNC termination. Set
generator for HIGH AMPL. Set Period to 10 kHz and
adjust Pulse Amplitude for a 5-division display.
c. ADJUST-R13 (CH 1 MF/LF GAIN) and C l (CH 1
MF/LF COMP) for the flattest response (within 0.25
division).
7. CH 1 Input C ap acitance ( C l 14)
a. Set:
CH 1 VOLTS/DIV
SEC/DIV
5 -8
b.
CH 2 (CH 1 off)
c.
GND
d.
8.
a.
b.
c.
9.
a.
b.
c.
10. CH 1 Gain (R 211)
a.
CH 1 (CH 4 off)
b.
50 mV
DC
50
)j.S
c.
11.
a.
10 mV b.
0.2 ms
Add precision normalizer between termination and
CH 1 input connector. Set calibration generator Pe­
riod to 1 kHz and adjust Pulse Amplitude for 5-divi­
sion display.
A D JU S T -C l 14 (CH 1 INPUT CAPACITANCE) for
best flat top.
Remove precision normalizer from the input cable.
CH 1 Input C om pensation X I 0 (0 1 1 )
Set:
CH 1 VOLTS/DIV
SEC/DIV
Set calibration generator Period to 10 kHz and adjust
Pulse Amplitude for a 5-division display.
A D JU S T -C l 1 (CH 1 INPUT COMP X I0) for flattest
response (within 0.25 division).
CH 1 Input C om pensation X I 00 (C IO )
Set CH 1 VOLTS/DIV to 1 V.
Set calibration generator amplitude for a 5-division
display.
ADJUST—CIO (CH 1 INPUT COMP X I00) for flattest
response (within 0.25 division).
Set calibration generator to STD AMPL and Ampli­
tude to 50 mV. Remove 50 f l termination from input
cable.
Set:
CH 1 VOLTS/DIV
SEC/DIV
ADJUST—CH 1 GAIN (R211) for exactly a 5-division
display amplitude.
CH 2 M F /L F Gain (R 23) and C om pensation
(C2)
Set:
Vertical MODE
CH 2 VOLTS/DIV
CH 2 COUPLING
SEC/DIV
Move calibration generator signal to CH 2 input. Add
50 f l termination.
0.1 V
50 |i.s
10 mV
0.2 ms
CH 2 (CH 1 off)
50 mV
DC
50 |is
REV JUN 1991