Motorola Astro Digital Mobile Radio Xtl5000 Detailled 6881096c74 B Manual

6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-61
5.6.47 RF Power Amplifier (RFPA)—No or Low TX Power Output (700–800 MHz)—
Part 4 of 5
Specific Notes:
1. Remove C6501 and solder the center conductor of a small 50-ohm, coaxial cable to 
VN_B6500. Solder ground to the gold shield track adjacent to VN_B6500. Attach an RF 
milliwatt meter, key the transmitter, and measure TX_INJ power. Then, remove the coaxial 
cable and replace C6501. Remove the solder added to shield track.
2. Remove R0977...

May 25, 20056881096C74-B
5-62Troubleshooting Charts: Flowcharts
5.6.48 RF Power Amplifier (RFPA)—No or Low TX Power Output (700–800 MHz)—
Part 5 of 5
Table 5-7.  RFPA DC Voltages
DescriptionLocationVo l ta g e  ( V d c )
A+ = 13.6 Vdc
U5501, VD1 VN_B6503 9.0–9.3
U5501, RFOUT VN_B6504 9.0–9.3
Q6520 Gate Bias VN_B6520 2.0–2.2
Q6520 Drain Bias L6521/R6526
Node13.0–13.6
Q6540 Gate Bias VN_B6540 3.5–3.7
Q6541 Gate Bias VN_B6541 3.5–3.7
Q6540/Q6541
Drain BiasL6542/R6544
Node13.0–13.6
Antenna Switch Bias...

6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-63
5.6.49 RFPA Power Control—No K9.1V (700–800 MHz)
Figure 5-49.  RFPA Power Control—No K9.1V (700–800 MHz)
Read General
Notes before
proceeding. Read
specific notes as
indicated
START
Is 9.3V present at
Q0952, pin 5?YesIs Q0952, pin 4 
 < 0.5V when mic
button is depressed?Repair/replace
Q0952 Yes
No
Is K9.1V_EN > 2.0V
when mic button is
depressed?No
Repair/replace
Q0951
Is A+ present at U0951,
pin 4?
No
Yes
See GPIO in
CONTROLLER
section...

May 25, 20056881096C74-B
5-64Troubleshooting Charts: Flowcharts
5.6.50 RFPA Power Control—No VGBIAS (700–800 MHz)
Figure 5-50.  RFPA Power Control—No VGBIAS (700–800 MHz)
Read General
Notes before
proceeding. Read
specific notes as
indicated
START
NoYes
Repair/replace
U0960
No
No/low Q6540
VGBIAS1?
No/low Q6541
VGBIAS2?
Remove U0960.
TP0937 voltage
 2.6-2.8 V? Yes
Remove U0960.
TP0939 voltage
 2.6-2.8 V? Yes
Remove U0960.
TP0941 voltage
 2.0-2.2 V? No
Repair/replace
U0959.  If problem
still not fixed,...

6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-65
5.6.51 RFPA Power Control—No or Low TX RFPA_CNTRL (700–800 MHz)—Part 1 of 2
For each flowchart step in which reference is made to a note, be sure to refer to that specific note 
(located on page 66 of this flowchart) for guidance in performing the actual troubleshooting 
procedure.
Figure 5-51.  RFPA Power Control—No or Low TX RFPA_CNTRL (700–800 MHz)—Part 1 of 2
Read General
Notes before
proceeding, Read
specific notes as
indicated
START...

May 25, 20056881096C74-B
5-66Troubleshooting Charts: Flowcharts
5.6.52 RFPA Power Control—No or Low TX RFPA_CNTRL (700–800 MHz)—Part 2 of 2
Specific Notes:
1. Remove Q0954. If proper power is restored, repair/replace Q0954. If the problem still 
persists, check for proper operation of U0958-1, and replace U0958 if not functioning 
properly. If U0958-1 operation is correct, refer the controller section in the theory of operation 
chapter.
2. Remove D0950. If proper power is restored, inspect R0942-5,...

Chapter 6 Troubleshooting Waveforms
6.1 Introduction
This chapter contains images of waveforms that might be useful in verifying operation of certain parts 
of the circuitry. These waveforms are for reference only; the actual data depicted will vary depending 
upon the operating conditions.
Table 6-1.  List of Troubleshooting Waveforms
WaveformPage
Power-On Reset Timing6-2
Power-On to Soft Turn-On Timing6-2
Power-Down Reset6-3
16.8 MHz Clock Waveform6-3
32 kHz Clock Waveform6-4
DSP SSI Port RX Mode6-4...

May 25, 20056881096C74-B
6-2Troubleshooting Waveforms: XTL 5000 Waveforms
6.2 XTL 5000 Waveforms
6.2.1 Power-On Reset Timing
6.2.2 Power-On to Soft Turn-On Timing
MAEPF-27853-OCh3Ch1M5.00ms
Ch16.0 VCh2
U0507 Pin 5
LV_DETECT (POR) 13.8V
Ch1
SWB+
5.00V
2.00V2.00V Ch2
MAEPF-27854-O
Ch3Ch1M  200ms
Ch16.0 VCh2
U0507 Pin 5
LV_DETECT (POR)
Ch3
TP050013.8V
Ch1
SWB+
5.00V
2.00V2.00V Ch2 

6881096C74-BMay 25, 2005
Troubleshooting Waveforms: XTL 5000 Waveforms 6-3
6.2.3 Power-Down Reset
6.2.4 16.8 MHz Clock Waveform
MAEPF-27855-O
Ch3Ch1M 10.0ms
Ch16.0 VCh2
U0507 Pin 5
LV_DETECT
Ch3
TP0500
SOFT_TURN_OFFCh1
SWB+ 13.8V
5.00V
2.00V2.00V Ch2
Power-Down Reset
Trace 1 — SWB+
Trace 2 — LV_DETECT — U0507 Pin 5
Trace 3 — SOFT_TURN_OFF — TP0500
MAEPF-27856-O
Ch1M  25.0ns
Ch110mV 500mV
C1 Pk-to-Pk
1.70V
C1 Period
59.333ns
Trace 1 — U0903 Pin 3 — 16.8 MHz Clock 

May 25, 20056881096C74-B
6-4Troubleshooting Waveforms: XTL 5000 Waveforms
6.2.5 32 kHz Clock Waveform
6.2.6 DSP SSI Port RX Mode
MAEPF-27857-OTrace 1 — R428 — 32 kHz Clock
2
Ch3 Ch1T
1
3
M 20.0us  Ch1           2.2 VCh1 Freq
18kHz
5.00V
5.00V5.00V Ch2
MAEPF-27858-O
DSP SSI Port RX Mode CSQ
Trace 1 — ABACUS_SSI_FSYNC
Trace 2 — ABACUS_SSI_RXD
Trace 3 — ABACUS_SSI_CLK (1.2 MHz)