Service manual
PN 4237242C
4.12-1
SERVICE AND REPAIR PROCEDURES
+24 VOLT SWITCHING POWER SUPPLY
4
4.12 +24 VOLT SWITCHING POWER SUPPLY
Tools/Supplies Needed
B #2 Phillips-head screwdriver
B Large flat-blade screwdriver
Removal
1. Turn OFF the instrument’s power.
2. Disconnect the ac power cable.
3. At the rear of the instrument, loosen the three captive thumbscrews (Figure 4.12-1) at
the top of the rear panel drop-down door. These thumbscrews are recessed and may
require the use of a large flat-blade screwdriver.
Figure 4.12-1 +24 V Power Supply
4. Drop down the rear panel.
5. Disconnect the three ac input wires from the power supply. They are attached to a
three-position terminal strip (Figure 4.12-1).
AC POWER
COMPUTER POWER
RTN
+
RTN
+
V1
-V4 +
-V3 +
-2V +
+S
-S
ON/OFF
PF/PG
7242020A
RTN
+
RTN
+
V1
V4
ADJ
V3
ADJ
-V4 +
-V3 +
-2V +
+S
-S
ON/OFF
PF/PG
OUTPUT LINES
(to J15)
+24 V
POWER SUPPLY
MOTOR/SOLENOID
DRIVER CARD
REAR VIEW (PANEL DOWN)
POWERFAIL SIGNAL
+24 V RETURN LINES
+24 V
POWER ON SIGNAL
AC INPUT
WIRES
(3)
FROM
SWITCHING
SUPPLY
ACL
ACN
THUMBSCREWS(3)
C