RM-11
Troubleshooting - RF CC Technical Documentation
Page 60 ©2005 Nokia Corporation Confidential Issue 2 09/2005
Rx DC Troubleshooting N750
Eventually, you will run into an N750 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 N750.
Condition (Local Mode, Set
Rx only in RF Main Mode)
Supply Current (from Power Supply)
Good mobile terminal 104mA
No UHF LO Signal present 254mA
Pin 13 shorted 255mA
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