76 Reciter Fault Finding TB8100 Service Manual© Tait Electronics Limited September 20063.5 Initial ChecksThese initial checks will verify whether:■ the reciter powers up correctly■ the reciter is correctly configured■ any alarms have been generated■ the 12.8MHz clock is running.Task 1 —Check DC Supply 1. Before starting any of these fault finding procedures, you must iden-tify the model and hardware configuration of the reciter under test.“Identifying the Reciter” on page 70 explains how to identify areciter from the product code printed on a label on the rear panel.2. Set up the test equipment as shown in Figure 3.2 on page 73.3. Power up the reciter using the standard test voltage of 28VDC.4. Check that the current drawn is within the specified limits. Thecurrent should be as listed in Table 3.1. If the current drawn iscorrect, go to Task 2. If it is incorrect, go to “Visual Inspection” onpage 82.Note All measurements must be made at least 20 seconds after power-up. This allows the DSP and RISC to power up and initialise thereciter. Any measurements made during the first 20 seconds afterpower-up will be incorrect.Table 3.1 Typical operating current figures for the reciterReciter Configuration Typical Currentdigital board only 90mA ±5mAcomplete recitera, Rx and Tx ona. Digital board, RF board, and system interface board fitted and operational.B and C bandsH bandK and L bands285mA ±5mA290mA ±5mA286mA ±5mA
