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  1. Rleo6965

    A few quick questions

    Yes remove the 18K resistor as Davenn observed. All LED’s were connected to +12V and TDA2050 pin4 only completes the circuit to ground every time the signal goes low voltage. That is, LED’s should not light if there’s no audio signal.
  2. Rleo6965

    A few quick questions

    Look what I found. Davenn was right. There's no 18K resistor on input pin2 of IC.
  3. Rleo6965

    A few quick questions

    Your multimeter will confirm the right polarity of dc voltage. You can also look at label or sticker of your DC adapter that show a drawing of wire connector with corresponding polarity.
  4. Rleo6965

    Help removing a wiring harness. Please.

    Hot Air Hair blower might work.:)
  5. Rleo6965

    Help with voltage controlled switch

    Yes, just saw datasheet. It's an open collector output that can switch voltage up to 50V. I rely on components library of ExpressSch Software when I draw the diagram.:)
  6. Rleo6965

    Help with voltage controlled switch

    Very good observation twister. Thanks.
  7. Rleo6965

    Help with voltage controlled switch

    Try this circuit. It might work. You can change Mosfet and load components to your requirement.
  8. Rleo6965

    A few quick questions

    The question is. Can your 12V DC adapter can handle required current of your circuit?
  9. Rleo6965

    SF139E

    Reverse your test probe and try again. Edit: Ooops. It's a thermal fuse. I thought it's an IC. Never encountered this kind of component before.:D You should have a low reading. Regardless of probe connection.
  10. Rleo6965

    Help removing a wiring harness. Please.

    My last resort was to pry the top sides of plastic connector but this will deform the top side of connector.
  11. Rleo6965

    Help removing a wiring harness. Please.

    It should be easier to remove than the one in the right. Just hold on the wire near the 5 wire connector and slightly pull connector on each side before pulling it up. If still doesn’t work. Spray it with WD40 or Contact cleaner to lubricate 5 pins contacts.
  12. Rleo6965

    Help identifying Component

    Resistance of transformer was normal for pwm power supply. Try to connect resistive load to the power supply and also check if resistor and capacitor have not changed value on pin4 of FAN7554.
  13. Rleo6965

    Buying Multimeter

    Yes. http://www.ppeinter.com/Sanwa-Digital-Multimeter/Digital-Multimeter-CD770.html
  14. Rleo6965

    Help identifying Component

    14V would be closed to 15V. It's possible that pin7 voltage has exceeded 15V upon power on and FAN7554 have function momentarily and shutdown due to defective components on its load. You can confirm this by placing dc voltmeter on output connector and monitor it upon power on. You can also...
  15. Rleo6965

    LED tachometer project

    Maybe it’s better if you isolate first if LM2917 have varying dc output w/ corresponding input signal from car signal. This is to simply troubleshooting your circuit.
  16. Rleo6965

    Which online portal is best for buying electroincs?

    RS component and Element14.com ( formerly Farnell )
  17. Rleo6965

    Please help me ID this plug!!!

    How about removing that 3 prong plug and convert it with plug available to you..
  18. Rleo6965

    Help identifying Component

    Try measure dc voltage on +VCC or pin7 of FAN7554. You should meaure not less than 15V. FAN7554 will not oscillate if voltage was lower than 15V.. Check starting big resistor ( around 100k 2W ) and if burnt or changed value. If big resistor have correct value. Change filter capacitor connected...
  19. Rleo6965

    Short on a psu LS1904006A

    How about placing MOV to protect your power supply? I think the damaged choke was the first one. Place 1 MOV before the choke and another MOV after the choke. Next time your ps would not be lucky.:D
  20. Rleo6965

    Pulse width modulation

    My idea was to have a power transformer that have multi-tapped secondary with automatic selector switch to feed selected bridge rectifier then pass a voltage regulator. Voltage drop to series pass transistor therefore would be minimal. It's only an idea. But maybe it can be done. This is linear...
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