California Instruments 12000L-1P, Instruction Manual

Page: 118 / 151

INSTRUCTIONAL MANUAL 2750L-P/4500L-P/6000L-P
August, 2001 Rev. K
-114-
3. Remove the Keyboard/Display assembly by loosening the two captive screws on its front panel.
4. Unplug the ribbon cable from the Keyboard/Display assembly.
5. Remove the Oscillator Module, A11, by pulling up the package of PC assemblies.
6. The module is now removed. To replace the module follow these steps in reverse order. Make sure
the ribbon cable that plugs into the Keyboard/Display assembly runs between PC assembly, A12, and
the front panel.
6.11 AMPLIFIER REMOVAL/REPLACEMENT
If a fault has been found that indicates the failure of an amplifier module (assembly 4009-423), check the condition of
the +300 VDC fuses before replacing the amplifier. Refer to Figure 6-1 for the location of the fuses. Fuse F1 is for
phase A, F2 for phase B and F3 is for phase C.
CAUTION
Capacitor C1 may have up to +350 VDC after the input circuit breaker has
been turned off. Before inspecting fuses F1, F2 and F3, discharge C1. C1
may be discharged through a 5 ohm power resistor.
If it is determined that an amplifier module must be replaced perform the following procedure:
1. Turn off the input circuit breaker.
2. Remove the AC Power System top cover.
3. Remove the four #6 screws that hold the insulator that covers the amplifier module, A1, A2 and A3.
4. Remove any of the three amplifiers by sliding it up and over the guide posts.
5. The amplifier may be replaced by following this procedure in reverse order.
6. Check the amplifiers associated 10 amp and fuse and replace it if necessary. Refer to Figure 6-1 for
the location of the fuse. F1, F2 and F3 are for the phase A, B and C amplifiers respectively.
7. After an amplifier has been replaced, readjust its gain and the 1-phase adjustment. Refer to Section 4,
page 82.