NSD–1
Disassembly / Troubleshooting Instructions
PAMS Technical Documentation
Page 5
Issue 2 09/00
Nokia Mobile Phones Ltd.
Trouble Shooting
Baseband Troubleshooting
Each main portion of the circuit will be described in enough detail for the
troubleshooter to determine whether or not that part of the circuit being
evaluated is functional. It will be helpful to use the placement diagram,
which illustrates all of the necessary testpoints in the baseband circuit, to
troubleshoot the phone. The placement diagram is intended to be used
concurrently with this document.
Main Circuit Sections
Power Circuitry
There are two ASICs in the baseband section, which supply power to
most of the phone. CCONT is the main power management ASIC, and
PENTA is used to supply additional switchable regulators for use in RF.
Two discrete linear regulators are used as well.
CCONT
CCONT is the main power management ASIC. It’s features include eight
2.8V linear regulators, a linear regulator with adjustable output, a refer-
ence voltage output, a 5V switch mode regulator, an 8 channel A/D con-
verter, and 32kHz clock circuitry. Each of the main functions and signals
are described below, including information on how to verify correct opera-
tion.
Vbat
CCONT is powered directly from the battery voltage, Vbat. Since CCONT
is a uBGA, the physical connection of CCONTs power pins can not be ver-
ified. Vbat must be checked instead at the closest external component,
which is shown as TP1. Valid voltages are 3.1–4.1V and should always be
powered; assuming voltage is applied to the battery terminals.
Vref
Vref is used as a reference voltage both internal and external to CCONT. It
is switchable between the nominal voltages of 1.500V and 1.251V, with
the default at power up being 1.500V. The phone uses the 1.251V refer-
ence, so once flash software is running Vref should switch to 1.251V.
Check Vref at TP2. Valid voltages are 1.478 – 1.523V and 1.244 – 1.258V,
respectively.
Linear Regulators
1. Vbb
