Proximity Detector; General Notes; Proximity Detector Components - Nokia NHL-2NA Series Troubleshooting Instructions

NHL-2NA

Proximity Detector

General notes

In the production proximity detector problems are best located from calibration results.
Before starting troubleshooting with the help of this section, user should familiarize to
the calibration instructions.
When the user brings the phone to the service point complaining that handsfree won't
turn on, the problem can be either in the handsfree speaker circuitry, or in the proximity
detector. This chapter gives instructions how to repair the problem in the proximity
detector.
A good indicator that the proximity detector has caused disabling of the loudspeaker is,
that the phone has switched the audio back to the earpiece. If the audio is not switched
to the earpiece but also loudspeaker is not on, the problem is most likely in the handsfree
circuitry.
When the problem is located on the proximity detector, the first thing to do is to check
that proximity detector lenses are roughly OK. If any physical damage is found, replace
lens module before proceeding to detailed troubleshooting.
If the problem is not this simple, the best way to look for the problem is to use PD cali-
bration.
Remember that Proximity Detector has to be calibrated always when optocomponents or
optics are replaced! Calibration also has to be done, if AEM ASIC is replaced or if calibra-
tion settings are lost from PMM.

Proximity Detector components

From now on Proximity Detector will be referred to as PD.
Main components of PD are lenses, emitter (IRED CL-200-IR, V334, 4860009), RSENSE
4R3 (R347), receiver (photodiode BPW34FS, V335, 486J830) and a control block, which is
located on AEM ASIC (N226). Three external capacitors are part of the control block:
100n (C275) and 220p (C273 and C274).
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CCS Technical Documentation
Issue 1 07/02