Crown ce 4000, Руководство по обслуживанию

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CE 4000 Service Manual
Maintenance 4-4
130485-1 Rev. B
©2002 Crown Audio, Inc.
6. Disconnect the safety ground wire attaching the
back panel to the chassis.
7. Pull the back panel assembly the rest of the way
out of the back of the amplifi er.
4.3.7 Line Filter PWA Removal
1. Remove the back panel assembly (see Section
4.3.6).
2. Remove the four T15 screws that secure the
shield.
3. Disconnect the faston connectors before removing
the PWA.
4. Remove the four standoffs that hold the Line Filter
PWA to the back panel assembly.
5. Remove the Line Filter PWA.
4.3.8 BFG PWA Removal
1. Remove the back panel assembly (see Section
4.3.6).
2. Remove the T15 fl athead screw that holds the
metal cable shield to the chassis.
3. Remove the two T15 screws that hold the shield
to the Main PWA.
4. Remove the metal shield out of the chassis.
5. Disconnect the ribbon cable from the Main PWA
at J6. (see Figure 4.2)
6. Remove the tie-wraps securing the ribbon cables.
7. Remove the two T15 screws securing the BFG
PWA to the chassis.
8. Lift the BFG PWA straight up from the chassis.
4.3.9 Main PWA Removal
1. Remove the FlyBack PWA (see Section 4.3.3).
2. Remove the back panel assembly (see Section
4.3.6).
3. Disconnect the PFC coils and remove them from
the side panel of the chassis.
4. Remove the T15 fl athead screw that holds the
metal cable shield to the chassis.
5. Remove the two T15 screws that hold the shield
to the Main PWA.
6. Remove the metal shield out of the chassis.
7. Remove the knobs from the front panel.
8. Remove the nuts that secure the level controls
to the front panel.
9. Slide the level controls into the chassis.
10. Remove the air shroud from the Main PWA
heatsink.
11. Unplug the power switch wires at J26, J27, J28
and J29 on the Main PWA.
12. Remove the seven screws that secure the heatsink
assembly and coil assembly to the chassis.
13. Remove the seven orange- or blue-painted
screws that secure the Main PWA assembly to the
chassis.
14. Holding the heatsinks, lift and slide the Main PWA
straight up and backwards out of the chassis.
4.4 Troubleshooting
As mentioned earlier, the three steps to effective
repair are: Determine the symptoms; identify the
cause of the symptoms; repair the unit to eliminate
the cause.
Please troubleshoot based on the order listed below.
4.4.1 Troubleshooting Flyback Power Supply.
1. Nulls off the error amplifi er output of channel 1 by
placing a jumper between TP100 and TP104 (Jumper
1 in Figure 4.6).
2. Nulls off the error amplifi er output of channel 2 by
placing a jumper between TP200 and TP204 (Jumper
2 in Figure 4.6).
3. Defeat Undervoltage protection circuitry on BCA
side by pulling TP248 to +15V (TP254) (Jumper 3
Figure 4.6 Shorting Jumpers
in Figure 4.6).
4. Defeat Brown-out effect protection circuitry by
pulling TP249 to +15V (TP-6) with a jumper, as shown
Figure 4.7 Brown-Out Jumper
1
2
3
Jumper