voltage regulator heat problem?

Store Forums Defusable Clock Bugs/Problems voltage regulator heat problem?

This topic contains 7 replies, has 3 voices, and was last updated by  civi 4 years, 4 months ago.

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  • #486

    Joggle
    Member

    hello together,

    my fresh assembled clock doesn´t work correct, so I´m currently testing several things to find the errors. Main problem: The voltage regulator gets hot. Within one minute i can´t touch him without burning myself (educated guess: Temp > 50 °C). At this point I disconnect the 9V. While connected to 9V, the regulator works correctly (delivers 5V). I can communicate with the ATMega (via PC) and there is no shortcut due to soldering. You could help me a lot by answering folloing questions.
    a) Is the fast warmup of the regulator normal?
    If not:
    b) Are there any “measure points”, which i can use to find flaw?
    c) Any ideas?
    Every little hint or help is highly appreciated.

    Greetings from Germany,
    Joggle

    #990

    Michael
    Keymaster

    Are you sure you positioned the chips correctly? Please make sure the 74HC595 chip is in correctly (the print is upside-down, and notch to the right).

    Can you send a clear picture of the back of the board and the front? Please send GOOD pictures, not blury cell-phone pictures to support@nootropicdesign.com.

    #991

    Joggle
    Member

    Wow, that was a quick answer!
    Pictures send. I´m not the best in soldering, but as far as i can jugde it all connections are working. The area around the Alarmbutton is a little bit modified. The picture with flash looks too messy.
    The chips are in the right position. I checked the hardware by replacing the “loop code”with this:

    void loop() {

    while(Serial.available()==0);
    if(blank == true){
    blank = false;
    }
    int val = Serial.read() - '0';

    if(val == 0)
    {
    digitalWrite(LED_PM, LOW);
    digitalWrite(LED_ALARM, LOW);
    digitalWrite(LED_TOP, LOW);
    digitalWrite(LED_DET, LOW);
    Serial.println("All LED off");
    }
    else if(val == 1)
    {
    digitalWrite(LED_PM, HIGH);
    Serial.println("PM LED on");
    }
    else if(val == 2)
    {
    digitalWrite(LED_ALARM, HIGH);
    Serial.println("Alarm LED on");
    }
    else if(val == 3)
    {
    digitalWrite(LED_TOP, HIGH);
    Serial.println("Top LED on");
    }
    else if(val == 4)
    {
    digitalWrite(LED_DET, HIGH);
    Serial.println("Det LED on");
    }
    else if(val == 6)
    {
    Serial.println("Start listening");
    while(val != 5){
    if(buttonPressed(ALARM_BUTTON)){
    Serial.println("Alarmbutton");
    }
    if(buttonPressed(DET_BUTTON)){
    Serial.println("Detbutton");
    }
    if(buttonPressed(MIN_BUTTON)){
    Serial.println("Minbutton");
    }
    if(buttonPressed(HOUR_BUTTON)){
    Serial.println("hourbutton");
    }
    }

    }
    else if(val == 7){
    Serial.println("beeeep");
    beep(3800, 30);
    }
    else if(val == 8){
    Serial.println(hours);
    Serial.println(minutes);
    Serial.println(blank);
    }


    }

    Everything works except for the heat problem and the display.
    I have a multimeter and can maybe even get an adjustable powersupply.
    Waiting for instructions.

    #992

    Michael
    Keymaster

    I got your pictures and sent a reply. The problem is that you switched the chips around. The two small chips are not the same. The 74HC595 chip goes on the left, and the 74LS247 chip goes on the right.

    #993

    Joggle
    Member

    ouch how embarrassing. I even read the other thread where somebody did the same mistake.
    Interestingly the noses of my chips are looking different then the one on the pictures. My long nose is on the left just like in the examples.
    Well, thanks a lot for helping me.
    I will try and return the favour by posting future modifications in the forum.

    #904

    Joggle
    Member

    After 3 hours of work, i finally gave up on switching the chips. Good news: I have a new testplatform with everything but a Display, although i need a new defusable clock.

    Regards,
    Joggle

    #906

    Michael
    Keymaster

    Yeah, the chips can be very hard to remove. They were likely damaged anyway.

    #1933

    civi
    Member

    If your voltage regulator IC is getting heated up that indicates that it is being forced to supply a lot of current. Now the current being supplied by the voltage regulator IC might not be more that the absolute maximum as written in its datasheet but it still does get warm if proper heat sink is not provided for high current applications. A usage of high current by your circuit can indicate a lot of things as well such as faulty IC or something similar.

    pcb assembly

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