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NSD-6
Disassembly/Troubleshooting Instructions
Memories
MAD4 interfaces to three memories — Flash, SRAM, and EEPROM. All of them are pow-
ered by 2.8V (Vbb). During Flash programming, Vpp (signal name is Vff on schematic) is
driven with 3V at the PC flash stations.
Problems
Phone won't power up
Do a visual inspection. Verify that all parts are on the board correctly, and that none is
missing.
Check that the 32kHz clock turns on when attempting to power up.
Check the power circuitry. This includes VBAT, Vref, and all of the linear regulators, as
well as the Penta regulators. Verify also that the external regulator that powers MAD4
(LEADVCC) is functional – if present.
Flash Align
Test 9
High current: This indicates that the problem is likely caused by a shorted component.
Check orientation of major components (including RF), and check for shorts. Likely com-
ponents are those that are powered directly from Vbat such as CCONT, the PAs, and vari-
ous capacitors.
Low current: This indicates that CCONT is not powering on. Verify CCONT circuitry.
Test 10
Flash: Failure to flash is the main baseband failure. Check all the CCONT regulators,
especially Vbb, VR1, and VR6 for shorts. Check clocks and reset circuitry. Check for shorts
on the address, data, and chip enable lines on the memories and MAD4. If a short is
detected, it may be that it is beneath the BGA flash and may have to be replaced.
NOTE: There is no ROM software that can be run when the phone does not flash. There-
fore, it must be visually (or by Ohmmeter) determined whether there is an eventual short
between two or more of the address or data lines.
In the field
Cracked or broken solder may cause failures to occur. Reflowing some of the major com-
ponents may fix problems in case the phone is functioning errantly (some buttons may
not work, the phone may not ring, etc.) or may not power on anymore.
Battery will not charge
If the battery won't charge (phone won't allow the battery to charge), check CHAPS and
the charging circuit. It may also be necessary to verify the A/D functionality of CCONT
since this is the method of detecting battery type, charger type, etc.
Page 14
Nokia Mobile Phones Ltd.
PAMS Technical Documentation
Issue 1 04/01
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Table of Contents
Troubleshooting
