Nokia NME-2A Series - Page 15

P.A.M.S.
Technical Documentation
NME–2A
Troubleshooting Instructions
Page 15
Original 08/97
1.1. Check 13 MHz signal:
– RXI and RXQ > 0.3 V
PP
at 12.93 MHz.
– J702 input to 13 MHz filter > 0.5 V
PP
– Check RXPWR J705 = 5 ±0.1 V
– Check 8.5 RX TX SW J703 = 7.7 ±0.1 V
1.2. Check 71/13 MHz mixer:
– N701, 71/13 MHz mixer: pin 15 4.8 ±0.2 V
– Enable: pin 21 > 4 V
– AGC5: <0.5 V (<2.5 V in burst)
– Output: J702 2.75 ±0.1 V
– LO: pin 6 >–10 dBm, 232 MHz
1.3. Check 71 MHz signal:
– AGC1 to AGC4 low (AGC4<2.5 V in burst)
– N702: pin1 and pin14 4.8 V ±0.2 V
– Enable: pin 6 >4 V
– Input: pin12, 13 –50 dBm, 71 MHz
– Output: pin 4, 5 –10 dBm, 71 MHz
1.4. Check UHF mixer:
– LO C934: +9 dBm ±3 dB, 1014 MHz
– Signal in C722: –50 dBm, 947.07 MHz (–57 dBm input)
– Signal in C722: –30 dBm, 947.07 MHz (–37 dBm input)
– Signal out C726: –57 dBm, 70.93 MHz
1.5. Check 71 MHz amp:
– Output to filter: –35 dBm, 70.93 MHz
2. AFC (Input –57 dBm, channel 60, 947.06771MHz):
Checks the signal path, the VCXO and some parts of the demodulator.
The VCXO is tuned high, mid and low while the frequency deviation is
measured.
– 10 kHz < High < 20 kHz
– –5 kHz < Mid < 5 kHz
– –20 kHz < Low < –10 kHz