Nokia 8310 Repair Hints page 7

Customer Care Europe & Africa

SCCE Training Group

CHAPTER 2 PHONE SWITCHES OFF ITSELF

If this fault appears ensure that switching-off symptom is not the result of a too old phone software-version. SW-version

should be 4.04 or newer!

Also check that symptom is not caused by an insufficient charged battery. In case of doubt retest the phone with a new or

well charged battery. If this does not solve the problem, check the following:

check mechanical appearance of battery connector X101. Change part if spring contacts are bent, soiled or corroded.

check amplitude and frequency of 32.768kHz sleepclock-signal at J404, 1.9Vpp:

check amplitude and frequency of 13MHz system clock at R420, 320mVpp:

try to calibrate TX-powerlevels. It is possible that poweramplifier N700 is defect so that the phone switches off if you try

to tune the upper powerlevels because of too high current consumption.

check solderings and resistance of R102 (100kΩ). It has been observed that solderings of this part were responsible for this

fault in some cases, especially if phone switches off or resets after some minutes to some hours.

In case that phone switches off itself repeatly after 30 seconds, this could be the result of a changed Flash D450 or UEM D200.

Because of the data mismatch between both parts the watchdog will not be reset and the phone switches off itself.

CONFIDENTIAL

NHM-7

Date 28.02.2002

Checked by:

SCCE Training Group

7 (18)

Repairhints

Version 1.0 Approved

Approved by:

SCCE

Nhm-7