138 Power Amplifier Fault Finding TB8100 Service Manual© Tait Electronics Limited September 20068.6 Initial ChecksYou can use the TB8100 Service Kit and Calibration Kit to check the basicoperation of the PA without removing the cover.■ To check whether the PA powers up correctly and generates any alarms,carry out Task 1, Task 2, and Task 3.■ If the PA has low RF output power, go to Task 4.■ To check the operation of the ambient air temperature sensor board, goto Task 5.Task 1 —Check Power-upand LEDs1. Before starting any of these fault finding procedures, you must iden-tify the model and hardware configuration of the PA under test.“Identifying the PA” on page 129 explains how to identify a PA fromthe product code printed on a label on the rear panel.2. Set up the test equipment as shown in Figure 8.3 on page 134 (28VPA) or Figure 8.4 on page 135 (12V PA). Do not fit the front panelto the subrack.3. Power up the test set-up and check the LEDs on the front panel ofthe PA. These LEDs provide the following information about thestate of the PA:■ steady green - the PA is powered up■ flashing green - the PA has no application firmware loaded; usethe Service Kit to download the latest version of firmware,recalibrate the PA, and repeat this step.■ flashing red - one or more alarms have been generated; use theService Kit to find out more details about the alarms.If the PA powers up, go to Task 2. If it does not, go to “Visual Inspec-tion” on page 144.Task 2 —CheckConfiguration andAlarms1. Fit the front panel to the subrack.2. Run the Service Kit and connect to the base station. Onceconnected to the base station, ensure that it is in Run Mode.3. If you are testing a customer’s complete base station, read the basestation to load the PA’s configuration information into the ServiceKit.If you have only the customer’s PA, and you are testing it in a test basestation, program the default profile into the test base station. Changethe default frequency as required.4. Select Configure > Base Station > Channel Profiles. In the EditChannel Profile screen go to the Power Saving tab and check that:■ the Tx Keyup time is 2ms■ Sleep or Deep Sleep modes are not selected.
