User Manual - Rev AJ California Instruments7.4.6 Other No Output ConditionsIf one or more outputs (phase A, B or C) do not produce an output, it may be caused by anamplifier failure. Amplifier failures can either be input (PFC) or output related (Amp). Todetermine if this is the case, the cover of the amplifier has to be removed. Contact customerservice support@calinst.com before attempting to diagnose on your own.ink, the PFC power devices must be replaced. If not, they need to bechecked for continuity using a DMM or diode checker.edrive section of the board and the board itself may haveto be replaced. MX Systems with later generation 7003-716 PFC control boards generally willonly require replacement of the 2A gate fuses to restore functionaliI ks intact, o witches ay have shorted.The usual scenario is one or two of the IGBTs if the B+ device short. When these devicesshort, one or more of the 30A fuses (F1 through F8) on the DC power distribution board will beopen.An amplifier device failure is not audible at all so there may be no indication of this other thanchecking as follows:1. Measure the output voltage with Zero AC volts programmed.2. Remove any EUT from the o3. Turn output ON and measure ould4. If the output reads –225VDC on the low range and close to 0 Vdc on the high range, then itis almost certain that th s ices are shorted.Note that the measurement screen will not report the DC faulty output voltage in the AC mode,as the measurements in this mode are AC coupled. Therefore, it is necessary to measure at theoutput terminals with a DMM to determine the actual output. Alternatively, the MX45 can beswitched to AC+DC mode in which case the internal measurements can be used instead.If it is determined that it is an amplifier failure, the affected IGBT's need to be replaced. If nolocal service support is available, the amplifier may be exchanged completely. Contact customerservice support@calinst.comPFC failure denotes one or all three of the IGBT power modules on the large PFC heat shave shorted, and damaged the devices. This type of failure is sometimes accompanied by apopping sound as the large PFC power devices give out. To diagnose this failure mode, theamplifiers must be removed and the cover removed for inspection.If there is any sign of damageIn case of a PFC failure, older generation PFC control boards (7003-705 or 7003-712) may havsustained damaged in the isolated gatety.f the PFC section loo ne of the output amplifier s mswitch devices on one of the 4 heat sinks getis failed, the B- device will alsohorted. Usuallyutput connections.the AC and DC output. It sh be close to zero.e fuse i blown and 1 or 2 IGBT devfor module exchange information.7.5 Factory AssistanceIf the problem with the cabinet or one of the power modules cannot be isolated, contact thefactory for assistance.MX Series180
