Motorola MTR3000 User Manual

4-31
Audio Verification
Using CPS, set the SW
emphasis either De & Pre or
none and audio type RX & TX
Filtered Squelch or RX & TX
Flat respectively. Set channel
bandwidth for 25KHz. Set the
GPIO pins accordingly so the
proper PTT can be issued.
the rad
io will be based on
what mod limit value is set to
100%, 92%, etc. See BSM
chapter 12 for further
assistance.
This test assumes standard
RF input 60% full deviation
1KHz audio tone. Input level to
This test requires a full base
radio
.
Choose the appropriate audio
path below you intend to
verify.
MICROPHONE
J3000M7
Tx Audio
Backplane conn
J7
Pin 1
Emph Tx Audio
Backplane conn
J7
Pin 22
RECEIEVER
Base Radio rcvr
port.
Inject a 56mVRMS
1KHz tone into t
he
mic port and apply
front panel PTT.
Audio verification
complete
Is audio
present at
U1402 pin J2
MIC/ K2 for
TXAUD?
Replace Board
See Note 3
Is audio
present at
C2800?
Verify limiter and
splatter filter
Is audio
present at
U2800 p
in 7
and U2603
pin 8?
Verify U2607
connections
before replacing.
U2602/U2607/U2608
Analog MUX
Pin 5: +5v
Pin 2: GND
Pin 6: 5v or GND
Pin 4: Matches pin 1 if
pin 6 is 5v. Matches pin
3 if pin 6 is GND.
Verify Mic audio
input before
replacing U2800
or U2603.
Tx DATA
Backplane conn
J7
Pin 13
Limiter/Splatter filter
Probe between R2819 and R2822.
Level should be around 80mVRMS.
If level does not match, then refer to
the schematic to verify the limiter
circuitry. If level matches, then use
the schematic to verify the splatter
filter.
Inject a
80mVRMS
1KHz tone into the
TX_Audio port and
apply backplane
PTT.
Inject a 80mVRMS
1KHz tone into the
TX_Audio_PRE
port and apply
backplane PTT.
Inject a 80mVRMS
1KHz tone into the
TXDATA port and
apply backplane
PTT.
Is au
dio
present at
U1402 pin
K2?
Is there
demodulated
audio at BR
transmitter
output?
Is there
demodulated
audio at BR
transmitter
output?
Is there
demodulated
audio at BR
transmitter
See Note 4
See Note 4
See Note 4
output
?
Yes
No
Yes
Verify TDATA
input before
replacing U2800
or U2802.
See schematic for
assistance
No
Is audio
present at
DB25 pin 7?
Yes
Verify U2604
connections
before replacing.
No
Yes
No
Yes
No
Yes
YesNo
No
No
Is audio
present at
speaker?
Yes
Mic
Is audio
present at
U2603 pin 1?
Verify U2602
connections
before replacing.
Yes
Tx_aud
Verify TX_AUDIO/
TX_AUDIO_PRE
input before
replacing U2603.
No
Can the
volume be
adjusted using
tuner?
Yes Yes
Audio EEPOT U2601
Pin 9: +5v
Pin 7: GND
Pin 2: +2.5v bias
Pin 1: Audio in; 254mVRMS
Pin 10: Aud
io out; vary with tuner
setting.
No
Is audio
present at
C2858?
Verify high pass
filter and audio
eepot.
1
Is audio
present at
U2604 pin 7
and U2800
pin 8?
Verify U2608
connections
before replacing.
Yes
No
Yes
No
No
MIC or
TXAUD
Path?
HPF or
EEPOT?
Hpf
Eepot
Figure 4-16 Audio Troubleshooting Flow Chart (Sheet 1 of 2)

Motorola MTR3000 Specifications

General

Brand	Motorola
Model	MTR3000
Category	Accessories
Language	English