RTU5024 Not Working
RTU5024 is a good device for remote control applications .However , This device can stop working due to may reasons . The design of this product or the quality of the components used inside may be the reason these devices fails often . Since , There are many manufacturers we cant tell what will long last and what will not . The RTU5024 device that we have examined in our previous article , only have a P.T.C as a protection . Which means some of these devices are very vulnerable . That’s why you have to design the power supply of these devices properly . Even if the power supply is good these devices can go bad simply due to damaged components . We can troubleshoot and find out why is your RTU5024 device is not working and how to fix it .
Troubleshooting Power
The power circuit of this device take up about one fourth of the PCB area . There are three regulator ICs supplying the voltages required for the operations of each section . Any of these components can go bad . Power circuit is one of the frequent causes of not working RTU5024 device .Here is how to find out if there is a problem in the power circuit of the RTU5024.
Step 1
We are going to check whether the power input reaches the regulator ICs or not by checking the voltages . Take your multimeter and put it to the DC voltage checking mode .Connect the power to the RTU50324 gate opener . Put the multimeter probes on screws of the power terminal (As shown in the image) . Check whether your multimeter displays the supply voltage . If not , Check the power supply .
Step 2
Troubleshooting PTC
Take the back probe of your multimeter and connect it to the negative terminal of the power supply . Now , You only have to handle one probe (Red probe) when checking the voltages . Take the red probe and put it on the first pin of the P.T.C and check the voltages . It should display the input voltage . If not , Re-solder the power connector terminal and the P.T.C .
Step 3
Troubleshooting TPTC
Then put the red probe on the next pin of the P.T.C check the voltages . It should display the supply voltage as well . If not , You may have a bad P.T.C . or you may have a short circuit ahead .you need to check for the short circuit before replacing the P.T.C .
Step 4
Troubleshooting The Diode
Put the red probe on the cathode pin or pad of the diode and check the voltages (As shown in the image) . It should display the supply voltage . If not re-solder the pins of the P.T.C and the diode . Put the probe on the anode pad of the diode it should display a voltage less than 0.3v of the supply voltage (Vs-0.3v) .If not , The diode can be bad or there is a short circuit ahead .Replace the diode if there is no short circuit .
Step 5 – Checking the Output voltages
Troubleshooting regulators
Troubleshooting regulator 1
Put your red probe on the output pin of the switching coil of the first switching regulator IC . Your multimeter should display 5Vdc . If not , You have to replace the first switching regulator IC . But , Make sure there is no short circuit first .
the output voltage Regulator 2
Put your red probe on the output pin of the switching coil of the second switching regulator IC . Your multimeter should display 4.0Vdc(approximately) . If not , You have to replace the second switching regulator IC . But , Make sure there is no short circuit first .
Checking the output voltage of regulator 3
Lets check the output of the third regulator (AMS1117) check the voltage at the output pin (As shown in the image) .It should display 3.3v . If not the AMS1117 regulator IC is bad . Replace it , If there is no short circuit in the output power path.
Relay Circuit Troubleshooting
If you RTU5024 device responds to the SMS you send but fails to turn the relay ON , faulty relay switching circuit could be the reason behind not working RTU5024 device.
Step 1
Troubleshooting relay supply
First lets check the voltages at the relay coil . The first pin of the relay coil should display 5Volts . If not , Re-solder the relay pin and the capacitor pins of the 5Volt power supply. If that doesn’t fix the problem , You may have a damaged Switching regulator (PU2). If there is not short circuit , Replace it .
Step 2
Troubleshooting Switching circuit
To check the function of the relay circuit you can manually turn on the relay by shorting the 3rd and 4th pins of the opt-coupler (OP1) . If you can’t hear the contact point switching sound from the relay you may have a bad relay switching transistor (Q3). Replace the Q3 SMD transistor (part No: SS9013) . If you cant find a exact match , Replace it with any PNP transistor that have similar electrical characteristics.
Step 3
Troubleshooting Relay coil
To check the condition of the relay coil , Put the multimeter to resistance checking mode and put the probes to the coil pins of the relay . The multimeter should display a value near 40Ohms . If the value is near zero Ohms , You have a shorted relay coil . If the value is too big (>1Kohms) , You may have a open coil . The relay need to be replaced in both of these cases .
Step 4
Troubleshooting contact points Normally Open
To check the contact points of the relay , Put your multimeter into the resistance checking mode and put one probe in to the Common contact’s pin and other to the normally closed contact’s pin. The value on the multimeter should be near zero Ohm . If not you have a damaged relay contacts . Replace the relay .
Troubleshooting contact points Normally Closed
To check the other contact point (normally Open) you have to turn the relay ON manually or VIA SMS command . Once the relay is ON check the resistance between the pins of common and normally Open . The value should be a near zero value . If not , You have to replace the relay .
G.S.M Module Troubleshooting
Quentel M26 Pin Out Diagram
If the GSM module is the reason why your RTU5024 device not working , The easiest way to detect if there is a problem with the G.S.M module is by the signal LED . If the signal LED is not blinking , Which means G.S.M module may have a problem .However , Blinking LED doesn’t means that you have a good G.S.M module ether. It just means that G.S.M module is up and running . If there is any issue regarding signals and network , Clean the SIM port and clean the SMA male jack . For further troubleshoot of the G.S.M module you need an oscilloscope .
Make sure to check the voltages at the “VBat” pins . There should be around 4.0 volts in those pins . If not you may have a bad switching regulator IC or the transistor that turns ON that regulator is damaged . Check whether the transistor’s base receives the signal from the microcontroller to turn ON the regulator . That signal should be around 3.0 volts .
Troubleshooting Microcontroller
Troubleshooting Microcontroller
Some times damaged microcontroller or it’s pins can cause not working RTU5024 . Lets start by checking the power input to the microcontroller . The 14th pin is the VCC pin , Put the red probe on that pin . The multimeter should display 3.3 volts . If not , You may have a damaged regulator . Replace the AMS1117 regulator . Sometimes the microcontroller pins can also damaged due to high current flow or short circuit . To make sure a particular pin is working or not you can check the voltage at a specific pin when the pin state changed . E.g – The pin that turns the G.S.M module ON/OFF should be 0 volts when the RTU5024 plugged and it should go to 5 volts within few seconds to turn the G.S.M module ON . The pin that controls the relay action should be 3.3 volts when the relay coil is OFF and should be 0 volts when the relay is ON . By checking the voltages you can find out whether the pin works or not.
EEPROM IC troubleshooting
Troubleshooting EEPROM
If the controller fails to save the numbers on the controller it may due to a damaged EEPROM IC . Put your red probe on the 8th pin of the EEPROM and check the voltage . The multimeter should display 3.3 Volts . If that voltage is not present , You have to replace the AMS1117 regulator IC . To properly check whether the EEPROM IC works or not you need another microcontroller and communicate with the EEPROM VIA I2C pins .If the voltage at the 8th pin is OK and still the controller fails to save the numbers , Replace the EEPROM IC .
Conclusion
If your RTU5024 gate opener is not working it may due a damaged components . The reason for damaged components may very. Sometimes due to cheap components or due to weather conditions . This device can be easily repairable . Because , The replacement parts can be found easily. You can speed up the troubleshooting process by starting from the most likely section that can be damaged . The power supply section . Any short circuit or high current flow can damage this section of the PCB . The relay switching transistor can also be damaged due to high current flow through the coil of the relay . If you are replacing a component with a component that has different part number , Make sure that components electrical characteristics matches the original parts .