[424owe]

Descriptions:

---this not ready yet - but if I tell you sth wrong ,pls post in this threat ----



One of the difficultest errors you will try to repair is a dead phone.
Different Hard- and Soft probs can be the reason.

To repair a dead phone, you should have some knowledge about the important components that a phone need to work.


What is a mobile phone:

Every mobile phone is a little computer,

it has a CPU (Central-Processing-Unit)
a RAM (Random-Access-Memory)
a ROM (Read-Only-Memory - today this ROM is mostly placed
with a Flash),
and periphical devices:
differnt I/O interfaces like keyboard, displsy (keyboard & display together
sometimes called "MMi" [MenMashineInterface]) , serial Interface (COM,USB),
IrDa, Bluetooth, a sound interface, and really important: A RF interface to communicate with a Basestation.

What is a CPU:
A CPU is a couple of transistors that do nothing without them saying what to do.

What is a Ram?
A RAM is a couple of transistors that do nothing without them saying what to do.
A RAM is to storing information tempoary, you can write content in it or read out the content. A RAM loose all its informaton if the power supply is lost.

What is a ROM?
A ROM contains the Software for the CPU. This software tells millions of transistors what to do. A ROM needs no power to hold the information in it.

This three compontnts are connected via a Databus and a Adressbus. And they have their own adress-ranges.


What needs the processor to work:

Power supply of couse...
the most mobile phones has a powersupply IC.
This IC delivers most of the in a mobilephone used voltages - but not all.
(Sometimes this component is called ASIC [Aplication-Specific-Integrated-Circuit]
what only means, that this IC is only developt for this application.)
Most of the integrated circuits in those IC are standard voltage regulators (VREG) such as a 7803 or sth else controled by a little processor.
But there are some other components init.
E.g. a I2C Bus connection, a I2S connection, a PA for the speakers, battery charge control,
a reciver for the watchdog signal from the processor.
3 switch on sensors (on/off1-KB7, on/off2-RTC_INT , Power from charger)
a.sth.e.

Some Important parts of the Power Supply Asic:

--

WA_DOG: (watchdog)

Status:
Switch on: important
Network : unimportant

If the processor halt 'couse of
an error or a HLT-command, it terminates the watchdog.
If there is no watchdog signal from the processor the ASIC shutdown atfer one second. Watchdog signal is a ca. 1 Hz digital signal.

--

I2C Bus:

Status:
Switch on: unimportant
Network : unimportant

This bus is to control the powersupply IC by the processor. The processor can tell the
ASIC to switch on and of single voltages (but this option is unused) - and this bus can be used to tell the processor measured voltage values and sth. else.

--

I2S Bus:

Status:
Switch on: unimportant
Network : unimportant
Sound : important

A I2S bus can transport sound in cd-audio quality from processor to ASIC. Mostly used for playing MP3 sound.

--

RTC_INT(erupt):

Status:
Switch on: unimportant, but can be used to switch on the mobile.
Network : unimportant


is to switch on the ASIC by the GOLD.
If the mobile is switched off, and a battery is insertet, the clock
(RTC) is runing well, and if there is a alarmtime programmed, RTC_INT goes H at alarmtime - to switch on your mobile and waking up you....

--

RESET:

Status:
Switch on: important
Network : unimportant

Reset is a 2,5V H Level that comes up after 250ms (newer models: 167ms) after switching on the powersupply.
To control the resettime there is a capacitor or a resistor assemled on the R_REF pin to GND.
The reset-signal is very important for all logical components. If reset stay L the locical components stay in reset mode. The components run when reset goes H.
The delaytime is important - becouse all components should reset during switch on. But first the supplyvoltages must be up.

Reset on L:
executes a reset. If you connect RESET to GND during your mobile is working, it will restart.

If reset stay on L-level becoue shortconnection or its open:
The mobile wont switch on.

--

R_REF:

Status:
Switch on: important
Network : unimportant

Reset reference for reset delaytime at startup.
This track has only a capacitor or a resistor connected to GND.

-----------------

different voltages:

in some series all voltages are named VREG_[component Name]
VREG_A or VREGA - that means: VoltageRegulater_Analog
VREG_RF1 or VREG_RF2 :VoltageRegulator_RadioFrequency1
or is simply numbered e.g. VREG1, VREG2 ect.

--

CCVCC (VREG_CC)

Status:
Switch on : unimportant
Network : unimportant
SIM : Important

is not importatnt for switching on, but what you doing with a phone that cant read a SIM-Card? - Only SOS Call.

ChipCard suply voltage.
It ist to suply your SIM-Card
In very very old Models 5V, in very old Models 3V and 5V,
in old models 3V and 1,8V, in newest Models only 1,8V.

--

VCC2,8V / VDD_RF1 / VREG_RF1 :
- in C60 and MC60 unused but enabled

Status:
Switch on : unimportant
Network : important
Stanbytime : TP840 problem (C60/MC60)

Own voltage-regulator for the RF IC and PLL's arround it.
VCC 2,8V is controled by the SLEEPQ signal.
In older models the VCC2,8 voltage regulator was a single part.
If no 2,8V there becouse short connection or missing SLEEPQ your mobile says: "No Network"


--


VCC_SYN (2,8V) (VDD_RF2, VREG_RF2)
- In C60/MC60 used for the complete RF part (but not PA).

Status:
Switch on: important
Network : important

- Supplys the very important 26MHz mainclock circuit.
(in older models only the supply for the 26MHz/13MHz mainclock, and a single part)
This Voltage is controled by the:

--

VCXO_EN(able) / VCOEN / VCXOEN_uC signal

Status:
Switch on: important
Network : important


- this makes the
processor able to switch off its mainclock to go in sleepmode and
to sleep with the 32,768 KHz RTC - it is to save battery energy.

If missing VCC_SYN becouse of shortconnection or missing VCXO_EN the mobile won't switch on.

--

VDD_RTC / VRTC

Status:
Switch on: important
Network : unimportant

This voltage is for the CPU integrated Real-Time-Clock.
Outside of the processor is a 32KHz cristal, mostly covered in a plastic case (named Z100,Z101,Z171 in shematics).
This voltage comes up as a battery is inserted.
It is buffered with a 10µ capacitor that makes you able to place the battery without loosing date and time.
It delivers also the H-Level for the ON/Off key via a resistor to KB7.

If missing this voltage there is no reaction and no current-consumption while trying to switch on via On/off key.
The mobile seems completly dead - only charging possible.

--

Batt+

Directly connected to Powersuply ASIC, PA, IrDa
and some standalone voltageregulators.


--

VCC2,9V (older Models)

Status:
Switch on: important
Network : important if single tracks to GOLD are damaged.

Supply for GAIM, DSP, Halfrate-CoPro (very old models) ,
and switches, EMI Filter, IrDa together with Batt+
and sth else.
But now GAIM and Copro are itegrated in the GOLD.
GAIM is the part to control the RF timing and A/D D/A converter to transmit/recive speech data via GSM.
Supply for RAM and Flash (older Models)

In newer Models:
Supply for Flash in WriteMode (else 1,8V in NormalMode)
Supply for in Gold integrated parts like GAIM.


VCC2,9V (in newest phones):
missing

--

VDD_A(nalog)

description later

--

VDD_Dig(ital)

description later

--

1,5V

description later

--


a functional main Clock (Reference Oscillator, RefOsc) (26MHz / 13MHz) of couse.




and a functional Data-/Adressbus:

The Adressbus:
The more memory the wider the adressbus. Today 24Bit wide.
The adressbus is to adress memory adresses - this can be RAM or ROM adresses.
If one track in the adressbus is shortconected to another or to GND or a supplyvoltage or is simply open, one or two bits on adressbus are wrong -
and also the adress shown on the adressbus is wrong. So the
data on the databus comes from wrong adress, and the processor recives garbage as a program to run.

-The processor halt.
-No WA_DOG sent.
-The mobile switch off.



The Databus:
In Mobile phones mostly 8 Bit wide. (newer models 16Bit)
The databus is to read/write data to the on the adressbus seen memory adress.
To decide reading or writing data from/to a memoryadress mostly a
write/read track is used (WR,RD). The state of this tracks H or L says the components reciving or writing data via the databus from/to the adress actualy seen on the adressbus.
The databus can be used to expand the adressbus, and the adressbus can be used to expand the databus.
Here is a track too, wich state decide this.

If one of those tracks are schortconnectet to another or open willt take the same effect as I said upwards.

-The processor halt.
-No WA_DOG sent.
-The mobile switch off.