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3/6/08
888-2463-001
5-25
WARNING: Disconnect primary power prior to servicing.
Section 5 Maintenance and Alignments
Diamond Series™
STEP 7
Adjust one of the Pallet bias pots (R7 or R10) for an indication of
25mVdc across R42 (25mV = 2.5amps) on the Driver Control Board.
Then adjust the other pot for an indication of 50mVdc across R42
(50mV = 5amps). For location of R42, see Figure 5-9.
Figure 5-9 Driver Control Board Component Locations
STEP 8
Allow several minutes of operation and then check the individual bias
voltages across R42 by shorting the bias to one pair of the RF transistors
(Q1,Q2 or Q3,Q4) then the other pair, to ground (this shuts off 1/2 of the
pallet). When the bias for either pair is shorted to ground, the voltage
across R42 should be 25mV, indicating that the operating pair is biased
to 2.5 amps.
To shut off the upper pair in Figure 5-8, short across R30, and re-adjust
R10 for 25mV across R42. To shut off the lower pair, short across R31
and re-adjust R7 for 25mV across R42. See Figure 5-8 for location of
R30 and R31.
NOTE:
If it is not possible to bias the pallet to 5 amps, then the pallet will have to be
replaced, or the whole driver sent in for repair. The latter is recommended if prob-
lems with re-biasing are encountered.
STEP 9
Turn OFF the driver by pressing S2 on the Driver Control board.