User Guide

6235/6235i/6236i (RM-60)

RF Description and Troubleshooting

Transmitter Troubleshooting Guidelines

Use some of the following guidelines when as you are troubleshooting.

• Always perform visual inspection of PCB under microscope to check proper

placement, rotation, and soldering of components.

• Look for presence of well-defined CDMA modulated signal on spectrum analyzer

at correct frequency. If signal is present but off frequency or shape looks

distorted, check synthesizer. Possibly, one of the synthesizers is not locked, or

VCO has no output signal. Check the synthesizers for proper frequency and

amplitude. See "Transmitter Output Spectrum" on page 20 and "Synthesizer

Troubleshooting"onpage43.

• Check that power supplies to transmitter have correct voltage See "Tx DC Test

Points"on page22.

• If signal is very low in amplitude, check probing diagram to determine what part

of TX chain is ‘broken’. See "Tx RF Test Points"on page23.

• Check that AGC PDMs produce and adjust TX power within the p r o p e r l i m i t s .

See Figure 9 on page 13, Figure 12 on page 16, and Figure 13 on page 18.

Transmitter Troubleshooting Setup

Use the following sets of procedures to troubleshoot the transmitter using Phoenix. Due

to the compact layout of the mobile terminal, some of the major test points are not

accessible without destroying the shield frames and the EL lamp. For example, duplexers/

diplexer/couplers test points are blocked by the test jig, the PA test points are

underneath the shield frame, and the BBIQ points are underneath the EL lamp.

To minimize effort, check the following in order:

1. Tx power at the RF connector.

2. All Tx DC points.

3. All soldering jig points for the whole Tx chain.

4. UHF LO presence:

• If the UHF LO is present, check the N7000 output.

• If the UHF LO is not present, it is a synthesizer problem.

5. If there is no N7000 output:

a. Change the N7000.

b. If the problem persists, reflow the duplexers, diplexer, and couplers.

c. If the problem persists, change the PA.

6. If there are several failed mobile terminals with the same symptoms, it may be

necessary to break one to determine the cause.

Use the following sections to set up troubleshooting in Phoenix according to the band