Advertisement
Customer Care Europe, Middle East & Africa
SCCE Training Group
If 942.6 MHz RX-signal at C534 is ok, check same signal at both sides of L504:
Amplitude at L504 approximately is –56 dBm. If signal is not ok, check solderings of T501 and C520/528.
Also check that attenuation of Z500 is not higher than 3.5 dBm.
If 942.6 MHz RX-signal at L504 is ok, check 67.708 kHz at the four pads of C512 located towards N500:
Figure 12-21
Channel 1 only shows the AC-part of the signal while channel 2 shows the same signal on it´s DC-level.
If 67.708 kHz are not measurable, check signals which HAGAR needs to work:
Check VTCXO 2.7 VDC at C506/518, VRXRF 2.8 VDC at C500/503, VSYNTE 2.7 VDC at C501/502/504 and
VCHP 4.7 VDC at C505. Also check HAGARReset at C540, SDATA at R300, SCLK/SENA at R301.
Refer to diagrams shown in section "No or too low TX-power GSM900".
Furthermore check signal of SHF-oscillator at T502 pin 3/4, 3770.4 MHz:
Figure 12-22
If SHF-oscillator does not work on expected frequency, check if voltage at C522 is 2.6 VDC. Also check control
voltage at C558, which varies between 1.2 V and 3.3 VDC. If control voltage is 4.8 VDC, the oscillator is faulty or
the control loop is open.
In case that it is necessary to rework G500 unfortunately you have to remove the RF-shielding first.
If all signals mentioned before are ok but no 67.708 kHz signal is measurable at the four pads of C512 located
towards N500, change HAGAR N500.
If 67.708 kHz at the four pads of C512 located towards N500 are ok, check 67.708 kHz on 1.7 VDC–level at all four lines of R500:
Figure 12-23
If signal is not ok, check C508 for shorts to ground, check resistance of R500 (4 x 100? ) or change HAGAR N500.
© NMP 2002
CONFIDENTIAL
NHM—2/5/6
3410
Date 20.11.2002
Checked by:
Customer Care E&A
41 (44)
Repairhints
Version 4.0 Approved
Approved by:
SCCE Training Group
Advertisement
