"Luminous Inverter Short Circuit Repair" Do you want to learn luminous inverter short circuit repair (dead condition inverter troubleshooting and repair), do you want to learn how to troubleshoot luminous inverter short circuits and open components. Are you searching for luminous inverter short circuit repair, luminous inverter short circuits and open components repair, troubleshooting luminous inverter PCB, luminous inverter PCB repair, repair of dead luminous inverter, dead luminous inverter repair, how to repair a dead luminous inverter, luminous inverter repair, luminous solar inverter repair, luminous ups repair or Inverter repair. If yes, Infoguide Ng has brought a complete step by step guide of how to repair a luminous inverter short circuit. This article will use Luminous Rapid Charge 1500 inverter as illustration. You can use the step by step guide here to repair other model of luminous inverter. This article cover the complete step by step guide of troubleshooting luminous inverter short circuits and open components. This article details the repair process for a Luminous Rapid Charge 1500 inverter that suffered a catastrophic failure. The inverter abruptly stopped working after an internal blast and smoke filled the unit, causing the main MCB (Miniature Circuit Breaker) to trip.
Initial Diagnosis and MOSFET Issues.
Upon opening the heavy inverter, the immediate visual fault was a blown MOSFET located on the first position of one of the heatsinks. The circuit board features two heatsinks, each typically holding four MOSFETs.
Testing the MOSFETs: The three pins of a MOSFET are the Gate (first pin), Drain (second pin), and Source (third pin). When the visibly damaged MOSFET was checked, the Gate, Drain, and Source pins were all shorted.
A crucial point in troubleshooting this circuit design is that if one MOSFET on a heatsink is shorted, all MOSFETs on that heatsink will appear shorted. This phenomenon occurs because the Source pins of all MOSFETs are connected by a single track, and the Drain pins are connected via the heatsink. Therefore, the fault tracing requires removing the bad component first to accurately test the others.
Addressing the Protective Circuitry
After removing the visibly damaged MOSFET, further checks revealed shorting on another MOSFET's Gate pin. This led to the discovery of a shorted Zener diode.
The Role of the Zener Diode: The Gate pin of a MOSFET receives pulses via a 15-ohm (15R) resistance. A Zener diode is installed in parallel with the Gate pin specifically for protection.
If a Zener diode is not installed, an overvoltage resulting from a shorted MOSFET can travel through the switching transistors and reach the main Microcontroller IC, potentially destroying it. The purpose of the Zener is to protect this main IC. If the Zener diode shorts, it typically causes the MCB or fuse to trip.
Upon disconnecting the shorted Zener diode, the shorting indication on the remaining MOSFETs immediately disappeared.
Troubleshooting the Power Failure.
Even with the initial shorting issues addressed, connecting 12V power (1 Amp) and pressing the power switch yielded no response. This indicated a voltage path was broken or missing.
- Checking the Minus (Ground) Path: The minus track was checked first. Three 40 Amp fuses (running in parallel) were tested in continuity mode and found to be intact. The minus track runs from the fuses, through a shunt resistor (labeled SH), and connects correctly to the Source pins of the MOSFETs. The continuity was confirmed to be okay.
- Checking the Plus (Positive) Path: The positive battery connection track was traced. The positive track leads through a diode and subsequently through a series resistor.
Identifying the Open Resistor: The diode was checked and, despite a temporary fluctuating value (likely due to a charging capacitor down the line), it was determined not to be shorted in series.
The resistance of the series resistor was measured in resistance mode. Although the color coding (Brown Black Golden) indicated it should be 1 Ohm, the multimeter displayed an incorrect value of 8.5 kOhms.
To confirm this component was the source of the power failure, the resistor was momentarily shorted while power was applied. Shorting the component immediately caused the inverter power to turn on. This confirmed the 1 Ohm resistor was open (or faulty).
Repair and Verification
- Resistor Replacement: The open 1 Ohm resistor had to be replaced. Since a 1 Ohm resistor was unavailable, a 2.2 Ohm resistor (which measured around 1.5 to 1.8 Ohms) was installed instead.
- Gate Pulse Check: After replacing the resistor and turning the circuit on, the critical step was checking the gate voltage on all MOSFETs. Proper gate voltage (or pulse) is necessary for all MOSFETs to function. Using a multimeter set to DC voltage mode, the first pin (Gate) of every MOSFET on both heatsinks was checked. All MOSFETs successfully showed a proper gate voltage of 3.7 Volts.
- Frequency Verification: A DSO (Digital Storage Oscilloscope) was used to check the stability of the gate pulses. The graph displayed proper pulses with no fluctuation and a consistent 50 Hz frequency across all MOSFETs.
- Final Component Installation: The circuit was disconnected to install the remaining protective and switching components.
- Zener Diode: The shorted Zener was tested using a Zener tester and confirmed to be an 18 Volt Zener. An 18V Zener was installed, ensuring the correct cathode/anode orientation (the silver or red stripe connects to the Source pin).
- MOSFET: The original MOSFET (identified by the number KE08 K3 K80) was replaced.
With the open resistor fixed, the protective Zener replaced, and the blown MOSFET replaced, the repair was complete.
Analogy: Troubleshooting an inverter circuit that has shorted components and open resistors is similar to tracing a city's electrical grid after a storm. If one junction box (the MOSFET) blows, it can temporarily short out the entire local neighborhood (the heatsink track). But if the main power line (the positive track) is cut by debris (the open 1 Ohm resistor), the whole district remains dead until that single critical line is restored, even if the other smaller faults are fixed.
You can follow this step by step guide to repair your luminous inverter short circuit.
You can also read Dead Luminous Inverter Repair Here.
Here's a video that explain Luminous Inverter Short Circuit Repair (dead condition inverter troubleshooting and repair).
