User Guide

RM-11
Troubleshooting - RF (Part 2) CC Technical Documentation
Page 26 ©2004 Nokia Corporation Confidential Issue 1 02/2004
Receiver DC Troubleshooting Alfred
Eventually, you will run into an Alfred failure that has the symptoms of high current in
local mode with just the Rx turned on. There can be two common explanations for this:
(1) No presence of an LO signal, and (2) input impedance drop shorting out one of the DC
supply pins to the chip. IMPORTANT: YOU MUST CHECK FOR BOTH CONDITIONS BEFORE
REPLACING THE CHIP. If you have no LO signal, refer to the section of this chapter on
troubleshooting the UHF LO. If you have a significant supply voltage drop on one of the
supply pins, then change Alfred.
Control Signals at RF-BB Interface
Figure 32: Control signals at RF-BB interface
Note: These components are located at the back panel. Check from SMD or missing components.
Table 2: Conditions and supply current values
Condition
(Local Mode, Set Rx only
in RF Main Mode)
Supply Current
(from power supply)
Good phone 104mA
No UHF LO Signal present 254mA
Pin 13 shorted 255mA