080515
228-1744 REV 3
5
KEPCO, INC.
131-38 SANFORD AVENUE
FLUSHING, NY. 11355 U.S.A.
TEL (718) 461-7000
FAX (718) 767-1102
http://www.kepcopower.com
email: [email protected]
6.
To gain access to the components of A4A3 in order to replace R58, R59 and R70, first remove A4A3 from the
chassis as follows:
a. At top of A4A3 disconnect nine cables from J1 through J9 of A4A3 (Figure 5).
b. Remove four screws attaching A4 assembly to the chassis.
c. Remove five screws and five washers attaching A4A3 board to A4A1 board and remove A4A3 board.
7.
Unsolder and remove the following three resistors from A4A3 and replace with the resistors supplied as fol-
lows (see Figure 5 for location of A4A3 components):
• Install and solder replacement R59 supplied: P/N 115-2597 (150K Ohms, 1%, 0.125W)
• Install and solder replacement R58 and R70 supplied: P/N 115-2809 (200K Ohms, 1%, 0.25W)
FIGURE 5. A4A3 COMPONENT LOCATIONS
8.
Reinstall A4A3 by following the reverse of step 6 above.
9.
Perform visual inspection of transition circuit installation.
CAUTION: After installing all components and wiring as described above, perform the following
checklist to verify that installation has been done correctly.
• Verify that cable wires are connected properly and to the correct termination
• Check for unintentional short-circuits between the wire connections and adjacent components, pads and
traces.
• Use an ohmmeter to verify that the Transition Circuit heatsink is isolated (more than 1Megohm resistance)
from the BOP chassis.
• Verify that the Transition Circuit is securely attached to the BOP chassis.
• Verify that the Transition circuit cables are clear of the Output Module (A2) Fan and Auxiliary Power Supply
(A5).
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