Motorola MTP700 Detailed Service Manual page 201

TRANSCEIVER 800 MHz
Open Loop Power Test (Cont.)
Perform LNODCT U803.
Perform the Open Loop
Power test again.
MTP700 Portable Radio / Detailed Service Manual
B
Measure the RF power at pin 24 of LNODCT
(U803) and input of I/Q splitter U801.
Is the level >0dBm?
Measure the RF power at input and output of I/Q splitter (U801)
Calculate the difference between I/Q splitter input and output.
Is the difference
>3.5dB?
Measure the ASW level on pin 28 of LNODCT
U803 during Tx slot by using scope. Does the
ASW level go low (about 0Vdc) during Tx slot?
Verify by using scope that:
1. There is 2.4MHz clock (1.8, 0.3Vdc) on pins 11, 12 of U803 during Tx slot.
2. SLT and SLTB go low on pins 9, 10 of U803.
Do the two
conditions exist?
Verify by using scope that there is an input data on pins 58-
61 of the LNODCT U803. (AC voltage 300-400mV peak)
Yes
Was any data
detected?
No
Perform Escort
section tests.
Yes
Check I/Q splitter U801, C827,
C828.
Yes
Replace faulty parts.
Perform the Open Loop Power
test again.
No
Yes
No
Yes
No
Replace LNODCT U803.
No
Perform the Open Loop
Power test again.
Perform "WPIC Test"
Perform the Open Loop
Power test again.
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