Nokia 6235 Service Manual

Nokia Customer Care

Baseband Description and Troubleshooting

6235/6235i/6236i (RM-60)

Issue 1 04/2005

©2005 Nokia Corporation     Company Confidential

Page 47

• Make sure phone was programmed/flashed

• Make sure phone is in local mode

• Make sure power supply provides enough current (usually approximately 500mA 

and 2A for tuning)

• Use the troubleshooting guide’s float chart to verify the failed circuit

• Check the signals and voltage levels per troubleshooting guide.

Refers to when no power causes phone to not able to flash, not to get into local mode 
and similar problems.

• Check baseband regulators – VR3, VIO, VFLASH1, VCORE dc/dc, PURX

• Check VCTCXO 19.2MHz signal at UPP input

• Check power up sequence

• Check Flash IC, flash bus signals, and voltage level

• Check for the absence of 32KHz SleepCLK 

• Check for incorrect SleepX and PURX signal levels

• Check if ESN number was corrupted 

• Check for bad contacts or damaged earpiece

• Check for bad connections at mic

• Check for broken or bad solder joint of passive components

• Verify the audio signal paths using BaseBand “audio test” component with 

Phoenix as described in the troubleshooting guide

• Check for protective film left on back of the key dome if a new one was installed

• Check for corrosion on both the key pads and key dome

• Check if flash software was corrupted

• Check for bad joint from UPP to Interface

• Check for pins shorted on or bad on Z300