Transmitter Troubleshooting; Low Tx Power - Nokia RH-57 Series Troubleshooting Manual

2112 (RH-57)
Troubleshooting - RF
• The phone is tuned and has passed tuning. (Read the tuning parameters using the
batch tune component in Phoenix; an untuned phone has all zeros in the tuning
file.)
• The call box channel is set for a channel in PRL.
• The SID is correct and entered into the phone.
• The MIN and MDN are entered into the phone.
• The VCTCXO is centered as described in the VCTCXO tuning description on
page 33.
• The transmitter and receiver are working properly in Local Mode.

Transmitter Troubleshooting

Low Tx Power

Use Phoenix to turn on the transmitter in Local Mode, and check the following:
• Verify the current (0.7 - 1A for max power, mode, and channel dependent).
• Use a microscope to visually inspect the PWB for proper placement, rotation, and
soldering of components.
• Look for the presence of a Tx signal on the spectrum analyzer at the correct
frequency:
• If the signal is not on frequency, check in the 100 MHz span.
• If the signal is present but off frequency, check the synthesizer. Most likely,
one of the synthesizers is not locked, or the VCO has no output signal.
• If the signal is not present, or is present but low in amplitude, use the
probing tables to determine where in the chain the fault occurs.
• Verify that the AGC PDMs are set for the desired Tx power as listed in the Tx AGC
Tuning table on page 12, and ensure that the AGC voltages are correct.
• Check the synthesizers for proper frequency and amplitude.
• Ensure that the power supplies to the transmitter have the correct voltage.
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©2004 Nokia Corporation
Nokia Customer Care
Company Confidential Issue 1 07/2004