
236
Transmitter Fault Finding
TP9100 Service Manual
© Tait Electronics Limited
May 2005
Task 12 —
Shaping Filter for
Power Control
If neither the voltage nor the current measured in Task 10 is correct, then
the shaping filter for the power-control circuitry or the CODEC and audio
circuitry is suspect.
Important
Ensure that the current limit on the DC supply is 2A. And,
when entering the CCTM command
331
x
, do not specify
a value
x
higher than that recorded in Task 9. Failure to do
so might result in the destruction of the PAs.
1.
Use the multimeter to measure the voltage at the via of
CDC TXFIN RXAGC
(see
). The voltage should be:
2.
Enter the CCTM command
331
x
(where
x
was recorded in Task 9).
3.
Check that the voltage changes to:
4.
Enter the CCTM command
32
to place the radio in receive mode.
5.
If the voltage measured above is correct, go to
. If it is not, go
“CODEC and Audio ault Finding” on page 269
6.
Check
IC101
and the surrounding shaping-filter circuitry
(see
). If a fault is found, repair it, confirm the removal
of the fault, and go to
. If the repair failed,
replace the main board and go to
Task 13 —
Biasing of
PA Driver —
voltage clamp
If the PA biasing and power control are correct, then proceed to check the
voltage clamp current of the driver.
1.
Enter the CCTM command
324 4
to set the radio to high power.
2.
Measure the voltage across the resistors
R122
,
R124
, and
R197
(see
for the B1 band and
for H5, H6).
The voltage should be:
3.
If the voltage is correct, go to
. If it is not correct, replace
Q106 and Q103. Confirm the removal of the fault and go to
. If the repair failed, replace the main board and
via of
CDC TXFIN RXAGC
: 64
±
2mV (initially)
via of
CDC TXFIN RXAGC
: 1.1 to 2.7V (after entry of CCTM 331
x
)
voltages across R122, R124, R197: < 0.3V (after entry of CCTM 324 4)
Summary of Contents for TP9100
Page 1: ...TP9100 portables Service Manual MPA 00005 01 Issue 1 00 May 2005 ...
Page 4: ...4 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 10: ...10 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 74: ...74 Circuit Descriptions TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 78: ...78 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 100: ...100 General Information TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 126: ...126 Disassembly and Reassembly TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 148: ...148 Interface Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 158: ...158 Power Supply Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 250: ...250 Transmitter Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 268: ...268 Receiver Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 294: ...294 Spare Parts TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 298: ...298 Antenna Identification Chart TP9100 Service Manual Tait Electronics Limited May 2005 ...