Troubleshooting Charts:
RX RF Failure
5-29
RX RF Failure – Page 3
2
Remove shield, SH9.
Measure RF levels at first
preselector filter and
compute filter loss.
UHF1/UHF2: Input side of
C1935 & output side of C1939.
VHF: Input side of C330
& output side of C339.
Loss < 3 dB?
Check components
and replace
defective parts.
Autotune the radio.
No
Measure RF levels at LNA
and compute LNA gain.
UHF1/UHF2: Input side of
C1931 and output side of C1936.
VHF: Input side of C339 and
output side of C360.
Gain about
15 dB?
Check LNA:
Check DC bias voltages of
UHF1/UHF2: U1932 at the
base (pin 1) & collector (pin 3).
VHF: U304 at the base
(pin 1) & collector (pin 3).
No
Is base voltage =
0.787 V?
Collector voltage =
1.56 V?
Replace
UHF1/UHF2: U1932
VHF: U304
Is base voltage =
1.022 V? Collector
voltage = 0.787 V?
Emitter voltage =
1.561 V?
Replace
UHF1/UHF2: Q1922
VHF: Q303
Check DC input line
voltages and visually
inspect and replace
defective components if
needed.
No
Yes
No
Yes
Measure RF levels at second
preselector filter and compute
filter loss.
UHF1/UHF2: input side of
VHF: input side of C345 & output
side of C357.
C1959 & output side of C1961.
Loss < 4 dB?
Check components
and replace
defective parts.
Autotune the radio.
No
Yes
5
Yes
Yes
Check DC bias voltages of
UHF1/UHF2: Q1922 at the base
(pin 2 or 5), collector (pin 3)
& emitter (pin 4).
VHF: Q303 at the base
(pin 2 or 5), collector (pin 3)
& emitter (pin 4).
Note: RF Test frequency used:
UHF1: 424.975MHz
700: 769.0625MHz
UHF2: 485.075MHz
VHF: Input side of C330 & output side of C339.
800: 860.0625MHz
Measured with a High Frequency Probe for relative comparisons and troubleshooting only.
Actual S21 gain or loss may differ if the test point is not 50 ohms.
Содержание Astro APX 3000
Страница 1: ...APXTM TWO WAY RADIOS APX 3000 DETAILED SERVICE MANUAL ...
Страница 2: ......
Страница 4: ...Notes ...
Страница 6: ...vi Document History Notes ...
Страница 10: ...x Table of Contents Notes ...
Страница 12: ...xii List of Tables Notes ...
Страница 18: ...xviii List of Figures Notes ...
Страница 22: ...xxii CommercialWarranty Notes ...
Страница 46: ...3 20 Theory of Operation Main Board Notes ...
Страница 84: ...3 58 Theory of Operation Bluetooth Notes ...
Страница 147: ...Troubleshooting Waveforms Clocks 6 3 6 2 2 4 MHz Clock Trace 1 Trace recorded at R6113 Figure 6 2 4 MHz Clock Waveform ...
Страница 154: ...6 10 Troubleshooting Waveforms Audio SSI 6 3 4 BCLK Trace 1 Trace recorded at R6107 Figure 6 9 Audio SSI BCLK Waveform ...
Страница 156: ...6 12 Troubleshooting Waveforms RX SSI 6 4 2 DA Trace 1 Trace recorded at R2805 Figure 6 11 RX SSI DA Waveform ...
Страница 157: ...Troubleshooting Waveforms RX SSI 6 13 6 4 3 FSYNC Trace 1 Trace recorded at R2804 Figure 6 12 RX SSI FSync Waveform ...
Страница 159: ...Troubleshooting Waveforms TX SSI 6 15 6 5 2 DA Trace 1 Trace recorded at R2817 Figure 6 14 TX SSI DA Waveform ...
Страница 160: ...6 16 Troubleshooting Waveforms TX SSI 6 5 3 FSYNC Trace 1 Trace recorded at R2807 Figure 6 15 TX SSI FSync Waveform ...
Страница 161: ...Troubleshooting Waveforms SPI 6 17 6 6 SPI 6 6 1 CLK Trace 1 Trace recorded at R2803 Figure 6 16 SPI CLK Waveform ...
Страница 162: ...6 18 Troubleshooting Waveforms SPI 6 6 2 CS Trace 1 Trace recorded at R6602 Figure 6 17 CS Waveform ...
Страница 164: ...6 20 Troubleshooting Waveforms I2C BUS 6 7 2 SCL 5V Trace 1 Trace recorded at R2204 Figure 6 19 I2C Bus SCA 5V Waveform ...
Страница 165: ...Troubleshooting Waveforms I2C BUS 6 21 6 7 3 SDA Trace 1 Trace recorded at R6209 Figure 6 20 I2C Bus SDA Waveform ...
Страница 169: ...Troubleshooting Waveforms USB 6 25 6 10 USB 6 10 1 D Trace 1 Trace recorded at TP F_GCAI_USB Figure 6 24 USB D Waveform ...
Страница 170: ...6 26 Troubleshooting Waveforms USB 6 10 2 D Trace 1 Trace recorded at TP F_GCAI_USB Figure 6 25 USB D Waveform ...
Страница 172: ...6 28 Troubleshooting Waveforms SDRAM 6 11 2 CLKX Trace 1 Trace recorded at TP6308 Figure 6 27 SDRAM CLKX Waveform ...
Страница 208: ...6 64 Troubleshooting Waveforms LF CW on Spectrum Analyzer Notes ...
Страница 222: ...7 14 Troubleshooting Tables List of Board and IC Signals Notes ...
Страница 282: ...8 60 Schematics Boards Overlays and Parts Lists Main Board Block UHF1 84012513001_A Notes ...
Страница 338: ...8 116 Schematics Boards Overlays and Parts Lists Main Board Block 700 800 MHz 84012501002 Notes ...
Страница 390: ...8 168 Schematics Boards Overlays and Parts Lists Main Board Block VHF 84012512001_A Notes ...
Страница 456: ...9 8 Debugging Fixture Powering up Covert Board Notes ...
Страница 468: ...Glossary 10 Glossary Notes ...
Страница 472: ...Index 4 Index Notes ...
Страница 473: ......