Nokia 8310 Repair Hints page 14

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G660

set phone with Phoenix on local mode

check VR3 2.8VDC at C662. With only this voltage the oscillator must be able to work on a frequency of 26MHz,

Otherwise you have to change G660. Check signal at C660:

AFC-voltage at C661 normally is 1.25VDC, but may vary between

0.05VDC and 2.5VDC.

If frequency deviation of G660 is >100Hz it is necessary to

change the oscillator!

G650, C653

to check if the SHF-oscillator G650 is working you have to activate with Phoenix e.g. TX-burstmode Ch.37. After that

check signal (3589.6MHz) at T650 pin 3 and 4 as shown below:

If no signal is measurable at T650 check VR7 2.6VDC at C650. If OK, set span of your analyser to e.g. 250MHz to check if the

oscillator works on any other frequency as on the supposed. If this is the case check control voltage at C652 which normally

is 2.1VDC on channel 37. In case of noise on the control voltage especially check C653 (tendency to leak).

If the oscillator does not work at all, change G650 and retest the phone.

N700

set phone with Phoenix to local mode and activate TX-burstmode Ch.37 (Ch.700 for GSM1800). Data in parethesis are

mentioned for GSM1800.

check VBATTRF 3.9VDC on both sides of L703

check incoming RF-signal of 897.4MHz at C731 (1747.8MHz at R705)

check VTXBGSM 2.8Vpp at C720 (VTXBDCS 2.8Vpp at C714) and VPDGSM 1.3Vpp up to 2.5Vpp depending on TX-power-

level at C719 (VPDDCS 1.2Vpp up to 2.1Vpp at C718):

check VTXLOGSM at R709. Signal/amplitude is the same as VTXBGSM, but it is only present in PA-free and -low mode.

If the above mentioned signals are ok but no or too low TX-power signal is measurable at L750 pin 1 (pin 3 in GSM1800),

it is necessary to change the poweramplifier N700.

CONFIDENTIAL

NHM-7

Date 28.02.2002

Checked by:

SCCE Training Group

14 (18)

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Nhm-7