User Guide

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

RF Description and Troubleshooting

VCTCXO Troubleshooting

Without 19.2MHz, the mobile terminal does not power up. This signal goes to the N7100,

N7000, D2800, and the UHF PLL. Check the test points in Figure 45 for the presence of

the 19.2MHz signal.

Figure 45: VCTCXO test point output values

If you do not see the VCTCXO signal at any of these points, check voltage at VR3, main

supply line for VCTCXO, it should be 2.78VDC.

Also check the AFC voltage, it should be between 1 and 3 volts. The voltage should be

adjustable with the AFC slider on the RF PDM Control in Phoenix. See "AFC Voltage

Troubleshooting" on page 49. If AFC voltage is missing, check the UEM.

VCTCXO Manual Tuning

The VCTCXO can be manually tuned to verify when a mobile terminal is tuned incorrectly

or if mobile terminal cannot make a call. Monitor the RF signal at the mobile terminal’s

output.

1. On the Phone Control dialog box, click the LOCAL button in the Phone State

area to put the mobile terminal into Local Mode. (See Figure 7 on page 11 for an

example of the Phone Control dialog box.)

2. Click the Execute button.