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P401
2.2 Connect a call.
To try GSM900, connect a call at powerlevel 5 and signal strength of -68.5dBm.
To try GSM1800, connect a call at powerlevel 0 and signal strength of -68.5dBm.
• If it works, proceed to section 2.3
• If it doesn't work, it's probably a Tx-related fault.
• If channel 1 (or several of the lower channels) is the only channel you can't con-
nect a call at, it's the N570 that's broken (class D2, fig. 2.2).
Open the phone and check for liquid damages.
Make sure the antenna connector (X101, class A, fig. 2.1) isn't damaged, badly sol-
dered or dirty (glue, varnish, oxide...).
Measure the resistance from the P401 (fig. 2.3) test point to ground (>10 kohms,
alternatively from N401 pin 14 to ground).
• If the resistance is too low, usually ~200 ohms, the N401 (class D1) has broken.
Check the solderings at N560 (GSM1800) and N570 (GSM900, fig. 2.2).
Check the solderings at Z205, Z203 (GSM900) and Z204 (GSM1800, all three class
B and in fig. 2.3).
4/00021-2/FEA 209 544/3.D
SH888, S868, Standare Electrical Repair
Fig. 2.3
Z205
Z204
L223
Z203
8
(66)
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