
6815854H01-A
June 15, 2005
Troubleshooting Charts:
Flowcharts
5-47
5.6.36 RX Back-End—Poor SINAD or No Audio (700–800 MHz)—Part 1 of 3
Figure 5-36. RX Back-End—Poor SINAD or No Audio (700–800 MHz)—Part 1 of 3
MAEPF-27806-O
Is the
IF level at
20dB
relative to the
RF input?
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Signal
present?
Voltage
level of >~3.5V
at Q6000
Collector?
Voltage
level of ~2.15V
at Q6000 Base
(pin 1)?
Measure Second LO
at C6026, top side
towards Abacus III
(U6000) pin
Refer back to
Receiver IF
troubleshooting
flowchart
Measure Abacus
0-3V Digital SSI
lines FS,DOUTA,
and CLKOUT
3
2
3
1
Are the
levels 0-3V?
No
Yes
Yes
Frequency
CLKOUT at
1.2MHz?
No
3
No
FS = 20kHz
sync pulse?
Frequency
is 75.6 or 71.1
MHz?
Inspect biasing components
and solder. Replace Q6000
as necessary
Yes
Visually inspect
the Second
LO VCO
Yes
No
Visual
examination
OK?
Make repairs
as necessary
No problem
found
DOUTA=
24-bit I, 24-bit Q,
8-bit AGC word?
Yes
Go on to RX audio
troubleshooting
flowchart
Check Voltage Regulator
U0505 for normal operation,
look for base to emitter
drop of ~1.2V on Q6001,
replace if necessary
START
Poor SINAD or
No Audio
Summary of Contents for XTL 1500
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Page 19: ...xviii List of Figures June 15 2005 6815854H01 A This page is intentionally left blank ...
Page 25: ...June 15 2005 6815854H01 A xxiv CommercialWarranty Notes ...
Page 35: ...June 15 2005 6815854H01 A xxxiv Model Numbering Charts and Specifications Notes ...
Page 49: ...June 15 2005 6815854H01 A 2 12 Product Overview Controller Section Notes ...
Page 161: ...June 15 2005 6815854H01 A 4 36 Troubleshooting Procedures Power Amplifier Procedures Notes ...
Page 225: ...June 15 2005 6815854H01 A 5 64 Troubleshooting Charts Flowcharts Notes ...
Page 429: ...8 2 Flex Cable Pin Out Lists Flex Cables June 15 2005 6815854H01 A Notes ...
Page 441: ...June 15 2005 6815854H01 A Glossary 10 Notes ...
Page 451: ...Index x June 15 2005 6815854H01 A This page is intentionally left blank ...