Motorola XTL 1500, Detailed Service Manual, Page: 239 / 452

June 15, 2005 6815854H01-A
6-14 Troubleshooting Waveforms: XTL 1500 Waveforms
Table 6-3. TX and RX Audio Path Test Points for 1 kHz Sine Wave
(for UHF R2)
Typical O-Scope Measured mV p-p Volts
Test Point Description mV RMS mV/div LL
1
UL
2
DC Bias
TX Audio Path
MIC_HI 80 mV RMS input 80 mV 20 226 227 3 to 9
TP0200 MIC_PREAMP_IN 80 mV 20 220 227 2.5
U0201-8 1st op amp out
3
0 mV 10 0 10 2.5
U0201-7 2nd op amp out 80 mV 10 210 227 2.5
U0201-1 3rd op amp and filter out 80 mV 10 210 227 2.5
U0201-14 4th op amp and filter out 80 mV 10 210 227 2.5
TP0203 CODEC op amp in 36 mV 10 85 117 1.42
U0200-17 Buffered CODEC in 36 mV 10 82 116 1.42
C0904 5 CF Out 150 mV 50 400 700 1.42
R6782 MOD_IN at 3 kHz dev.
3
150 mV 50 400 700 1.5
RX Audio Path
4
TP0204 RX_FILT_AUDIO 318 500 849 953 1.42
TP0205 RX_AUDIO_IN 318 500 849 953 1.42
TP0206 AUDIO_PA_IN 39 10 92 130 1/2 A+
SPKR+ NON INVERTED PA out 7.74 Vbtl
5
2 V 9.5 Vpp 12.4 Vpp 1/2 A+
SPKR- INVERTED PA out 7.74 Vbtl
5
2 V 9.5 Vpp 12.4 Vpp 1/2 A+
1
LL = lower limit
2
UL = upper limit
3
Measurement depends on tuning parameters
4
1 kHz tone at 3 kHz deviation, -47 dBm
5
“btl” = bridge to load