TB8100 Service Manual Power Management Unit Fault Finding 237© Tait Electronics Limited September 2006Task 3 —Check Plug-in Cardswith Another DCConverterIf the DC converter still fails to produce an output after testing the cards asdescribed above, the DC converter board may be faulty.1. Remove the plug-in cards from the DC converter under test and fitthem to another DC converter which is known to work.2. If this second DC converter works correctly, the DC converter undertest is faulty.3. Fit a new DC module to the PMU under test, reassemble the PMU,and go to “Final Tasks” on page 247.13.8.3 PMU Operation on DC InputThis section is a copy of the section that is published in the TB8100Installation and Operation Manual. It is reproduced in this manual for yourconvenience.Introduction The operation of the PMU on DC input is controlled by three sets ofparameters:■ user-programmable alarms■ user-programmable startup and shutdown limits■ battery protection limits.The voltage range for each of these parameters is provided in Table 13.4 onpage 239. Figure 13.9 on page 238 illustrates how these parameters interact,and how they control the operation of the PMU over a range of DC inputvoltages.Alarms User-programmable alarms can be set for low or high battery voltage. Thealarms will be triggered when the set voltage levels are reached.To set the alarms, run the Service Kit and select Configure > Alarms >Thresholds. In the Thresholds form, enter the required minimum andmaximum values in the PMU battery voltage fields.Startup andShutdown Limits The user-programmable startup and shutdown limits allow for adjustablestartup and shutdown voltages. These limits can be adjusted for differentnumbers of battery cells, or for the particular requirements of the basestation operation. Once the limits are reached, the PMU will shutdown.To set the startup and shutdown limits, run the Service Kit and selectConfigure > Base Station > Miscellaneous. In the Power Configurationarea, enter the required values in the Power shutdown voltage andPower startup voltage fields.
