User Guide
Table Of Contents
- Amendment Record Sheet
- Copyright
- Warnings and cautions
- For your safety
- Care and maintenance
- ESD protection
- Battery information
- Company Policy
- Nokia 1680c; Nokia 1681c Service Manual Structure
- 1 General Information
- 2 Service Tools and Service Concepts
- 3 Baseband Troubleshooting Instructions
- General baseband troubleshooting
- SIM related faults
- User interface
- Audio troubleshooting
- Audio troubleshooting using phoenix
- Check microphone using "Hp microphone in Ext speaker out" loop
- Check earpiece using "Ext microphone in Hp speaker out" loop
- Check IHF & ringing tone function using "Buzzer"
- Check vibra function using "Vibra control"
- Earpiece fault
- IHF/ringing tone fault
- Microphone fault
- Headset earpiece fault
- Headset microphone fault
- 4 RF Troubleshooting Instructions
- 5 Camera Module Troubleshooting (Only for RM-394/RM-395)
- 6 System Module
- Glossary

Signal
name
From To Parameter Min Typ Max Unit Function
AFC UEMCLit
e
VCTCX
O
Voltage Min 0.0 0.1 V Automatic Frequency
Control signal for
VCTCXO
Programmable
(AFCOUT
)
Max 2.4 2.55
Resolution 11 bits
Load
resistance
1 kW
and
capacitanc
e
100 nF
Source
Impedance
200 W
Output
impedance
10 MW Path powered down
TxC UEMCLit
e
RF-IC Voltage Min 0.1 V Transmitter power
level and ramping
control, Ref UEMCLite
RF converter
specification
(AUXOUT
)
Max 2.4
Source
Impedance
200 W
Resolution 10 bits
VCXOTEMP RF-IC UEMCL
ite
Input
voltage
range
0 2.7 V
Input
resistance
900 6000 Ohm
Resolution 10 bits
PATEMP RF-IC UEMCL
ite
Voltage at
-20oC
1.57 V Usage depends of the
RF design
LCD interface
The display is controlled by phone processor UPP.
The main LCD module is connected to the PWB by a 24-pin board-to-board connector.
Keyboard
A 5 X 5 matrix keyboad consists of 21 keys, one 10-channel integrated passive filter arrays with downstream
ESD protection of >8KV connect the matrix keyboard to UPP.
RM-394; RM-395; RH-118
System Module
Page 6 –14 COMPANY CONFIDENTIAL Issue 1
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