FM RADIO TROUBLESHOOTING CHART
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Phoenix: Testing
-> FM radio -> Power on.
FM signal:
Frequency = 100 MHz, frequency deviation = 67.5 kHz, modulation frequency
= 1 kHz, R=L,
pilot tone on and RF level -67 dBm. Signal is injected at X102
bottom connector
pin 11, 12, 13 or 14.
Alternative:
Use FM signal received by headset
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Measure audio
voltage a) VAFL = 200 mVpp
(1 kHz) 850 mVDC
(C380, both sides
b)
VAFR = 200mVpp (1 kHz) 850 mVDC (C382, both sides).
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Ok
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FM
Radio OK
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No
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Measure N356
supply voltages a) VCCD = 2.78 V (C359)
b) VCCA = 2.78 V
(C372)
d)VCOTANK1 = 2.78
V (L356)
c) VCCVCO = 2.78
V (C362)
e)
VCOTANK2 = 2.78 V (L357).
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No
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Check passives and
then go to
BB
troubleshooting.
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Ok
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Measure
N356 XTAL2 voltage = 600 mVpp (32.768 kHz) 1.7 VDC (C375)
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No
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Check
C374 and C375, then go to BB troubleshooting.
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Ok
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Measure
CPOUT voltage = 0.9 V @ 100 MHz (V356).
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No
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Check
V356, V357, L356, L357, R359, C357 and C358.
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Ok
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Measure
RF level at antenna input (C367).
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No
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Visual
inspect C110-C113, L103 (all bottom side, grid T5), C367, C378, C379 and
L358.
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