Power Doesn't Stay On Or Phone Is Jammed; Contact Service On The Phone Display - Nokia NSB-7 Series Service Manual

PAMS Technical Documentation
In flash programming error cases the flash prommer can give some information about a
fault. The fault information messages could be:
- MCU doesn't boot
- Serial clock line failure
- Serial data line failure
- External RAM fault
- Algorithm file or alias ID not found
- MCU flash Vpp error

Power doesn't stay on or phone is jammed

If this kind of fault has come after flash programming, there are most probably open
joints in ICs. Solder the joints of ICs. Normally the power will be switched off by CCONT
(N100) after 30 seconds if the watchdog of the CCONT can not be served by software.
This updating can be seen with an oscilloscope at CCONTCSX (J104). In normal case
there is a short pulse from "1" to "0" every 8 seconds. The power off function can be pre-
vented by connecting WDDIS (R118 edge side head) to ground.
Because of the under fill, check the supply voltages, clock signals and power up
sequence. If power on sequence fails, there are some open connections under MAD or
combomemory. If all seems to be correct, it is best way to erase the flash memory and try
to put new software to phone.

Contact service on the phone display

This fault means that software is able to run and thus the watchdog of CCONT (N100)
can be served. Self test functions are run when power is switched on and software is
executed from flash. If any of the self tests fails, a "contact service" text is shown on dis-
play.
MCU self tests are divided to those executed while power up (start up tests) and ones
that can be executed with connected PC. The tests and included items are as follows:
1. MCU ROM checksum
Calculates 16 bit checksum out of Flash code and compares it to one found in Flash.
Items being checked are:
MAD2 <--> Flash data and address lines, CE0,CE1, WE, BYTE, Vcc, GND, Flash internal
functionality
2. MCU RAM interface
3. MCU RAM component
4. MCU EEPROM interface
5. MCU EEPROM component
6. RTC battery
7. CCONT interface
8. A/D converter
9. SW reset
A. Power off
B. Security data
C. EEPROM tune checksum
Issue 1 06/00 ãNokia Mobile Phones Ltd.
Disassembly & Troubleshooting
NSB-7
Page 29