Service manual

8000 SERIES RECEIVER DECODER MODULE (RDM)
2-2
March 2000
Part No. 001-3139-502
2.4 DISCONNECT
Disconnect by the Mobile can occur one of two
ways. One way is when the RDM is no longer decod-
ing the subaudible “Word” from the Mobile. The
RDM sends a Receive Time-Out byte by the RS-232
to the RMM. The second way is when the RDM
decodes the Turn-off Code from the Mobile. The
RDM sends a Receive Turn-Off Byte by the RS-232 to
the RMM, see Figure 2-1
.
Figure 2-1 RDM BLOCK DIAGRAM
2.5 SWITCH SETTINGS
NOTE: Refer to Appendix A and B for frequencies.
Figure 2-2 TEST TONE RELATIONSHIP
2.6 800 MHz RECEIVER DRAWER ALIGNMENT
Refer to the alignment points and test setup dia-
gram in Figure 2-3 and proceed as follows:
(Refer to Appendix A for frequencies.)
2.6.1 FIRST OSCILLATOR FREQUENCY AD-
JUSTMENT
1. Set the frequency monitor to the first oscillator fre-
quency (Rx Freq + 45 MHz) and monitor the first
oscillator signal with a pickup loop.
2. Adjust C59 for the correct frequency.
NOTE: C60 can be changed to one of the values in
Table 2-3 to change the adjustment range of C59.
Increasing the capacitor value decreases the adjust-
ment range and vice versa.
Table 2-2 RDM SWITCH SETTINGS
Switch Section Description
S1 1
2
3
Any one section OFF sends the
RDM into board test.
S1 4 Off - Normal
On - Extended RVM operation
S1 5 ON - 9600 Baud for Revert link to
Remoted MLM.
OFF - 2400 Baud for Revert link to
MLM.
S1 6 ON - Receiver Revert Disable
OFF - Receiver Revert Enable
S2 1-10 FCC channel number
1 (MSB), 10 (LSB).
Table 2-3 C60 REPLACEMENT VALUES
Description Part Number
27 pF ±5% 50V NPO ceramic 510-3113-270
30 pF ±5% 50V NPO ceramic 510-3113-300
33 pF ±5% 50V NPO ceramic 510-3113-330
36 pF ±5% 50V NPO ceramic 510-3113-360
39 pF ±5% 50V NPO ceramic 510-3113-390