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5-92
Zero Output Current, Standard Instrument
With Variable Gain Voltage Programming. For instruments
using the remote programming setup shown in Figure 3-9,
zero the output current as follows:
a. Perform steps (a) and (b) of paragraph 5-91.
b. Solder a jumper between pads in zero adjust section
of A1 main circuit board that are marked "I" and "J" in
Figure 5-9.
c. Connect decade resistance box between pads marked
"K" and "L" in Figure 5-9. (These pads are for R115.)
d. Perform steps (d) through (f) of paragraph 5-91.
5-93
Zero Output Current, Option 021 Instrument
With Resistance or Fixed Gain Voltage Programming.
For Option 021 instruments using either local program¬
ming or the remote programming setup shown in Figure
3-7 or 3-8, zero the output current as follows:
a. Perform steps (a) and (b) of paragraph 5-91.
b. Rotate VOLTAGE controls fully clockwise and
turn on supply.
c. If reading on digital voltmeter is not exactly zero
volts, adjust potentiometer R119 (labeled "CURRENT
ZERO" and accessible through hole in rear panel) until
reading is exactly zero.
5-94
Zero Output Current, Option 021 Instrument
With Variable Gain Voltage Programming. For Option 021
instruments using the programming setup shown in Figure
3-9, zero the output current as follows:
a. Perform steps (a) and (b) of paragraph 5-91.
b. Rotate VOLTAGE controls fully clockwise and
turn on supply.
c. If reading on digital voltmeter is not exactly zero
volts, adjust potentiometer R116 (labeled "CURRENT
PROG" and accessible through hole in rear panel) until
reading is exactly zero.
5-95
Zero Output Current, Option 040 Instrument.
Zero the output current of Option 040 instruments as
follows:
a. Connect test setup shown in Figure 5-7, except omit
load resistor
and connect just current sampling resistor
Rg across the output of the supply.
b. Connect remote programming setup shown in Figure
3-7 and adjust remote resistance to zero.
c. Rotate VOLTAGE controls fully clockwise and turn
on supply.
d. If reading on digital voltmeter is not exactly zero
volts, adjust potentiometer R119 (labeled "CURRENT
ZERO" and accessible through hole in rear panel) until
reading is zero volts ±2mV.
5-96
Constant-Current Programming Accuracy,
Standard Instrument. To calibrate the constant-current
programming current of a standard instrument, proceed
as follows:
a. Connect test setup shown in Figure 5-7.
b. Disconnect strap between terminals A5 and A6 on
rear barrier strip.
c. Connect 0.1%, 1/8 watt resistor of value shown
below between terminals A4 and A6 on rear barrier strip.
Model
Value
6259B
200ft
6260B
200ft
6261 B
200ft
6268B
180ft
6269B
200ft
d. Connect decade resistance box in place of R30 (mount¬
ed on standoffs on main circuit board; see Figure 7-7).
e. Rotate VOLTAGE controls fully clockwise and
turn on supply.
f. Adjust decade resistance box until digital voltmeter
indicates exactly 0.5Vdc.
g. Replace decade resistance box with fixed, composi¬
tion, 5%, 1/2 watt resistor of same value.
5-97
Constant-Current Programming Accuracy, Option
021 or Option 040 Instrument. To calibrate the constant-
current programming current of an Option 021 or Option
040 instrument, proceed as follows:
a. Perform steps (a) through (c) of paragraph 5-96.
b. Rotate VOLTAGE controls fully clockwise and
turn on supply.
c. Adjust potentiometer R116 (labeled "CURRENT
PROG" and accessible through hole in rear panel) until
digital voltmeter indicates 0.5Vdc ±10mV.
5-98
Load Transient Recovery Time Adjustment
5-99
To adjust the transient response, proceed as
follows:
a. Connect test setup shown in Figure 5-4.
b. Repeat steps (a) through (k) as outlined in paragraph
5-30.
c. Adjust R47 until transient response to within
specification as shown in Figure 5-5.
5-100
Ripple Balance Adjustment
5-101
This procedure ensures balanced triac operation
by ensuring that its conduction time is within 25% of being
equal in both directions. To check for imbalance, proceed
as follows:
a. Connect load resistor specified in Figure 5-1 across
rear output terminals of supply.
b. Connect variable autotransformer between input
power source and power supply input and adjust it for a
230Vac input to the supply.
c. Connect ac-coupled oscilloscope across series regulator
(between TP102 and TP103).
5-19
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