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  1. dave9

    Heated Clothing Potentiometer Help

    ^ Because the circuit only SEEMS simple after they have spent the time to figure out how to do it. If you want to just duplicate what some video did and it seems like a sound design, that is different from rolling something else from scratch. A few things that are wrong with the original...
  2. dave9

    Heated Clothing Potentiometer Help

    You're totally ignoring the current in every part of the circuit. Your battery case may simply be too low end junk, or at least the wrong materials, to support what you're trying to do. Your battery may be undersized too, what good is staying warm for only a little while when people usually...
  3. dave9

    Underdriven 12V LED chips in a 120VAC system

    It might help if you linked to these 12V LED chips so we know how they arrived at that spec or claim. Some might be 1 to 3 LEDs in series with a resistor built in. Some might just be 3 in series, maybe even additional parallel series of three, but need a resistor or other current limiting in...
  4. dave9

    Need help to identify a component!

    ^ Thermistors are very common above 1A rating. They've been used for years to reduce inrush current in PC power supplies for example. Another random example: http://www.ussensor.com/inrush-current-limiting-power-thermistors
  5. dave9

    Switch Identification

    Do you really need that exact switch? Being panel mount, there should be a few dozen to choose from that perform the function and fit in the available space, and of course, meet the required electrical spec volts and amps.
  6. dave9

    Electric weed eater motor output question

    Weed eater motor is unlikely to have enough torque. Same for drill motor but it has reduction gearing to solve that. If you have gears, chains, pulleys, belts, etc lying around you might be able to rig up something but try to stay at the RPM a drill output produces so you don't burn up the...
  7. dave9

    Need help to identify a component!

    I know nothing specific to electrical circuits on a tractor, would do as mentioned above, look for markings on the other thermistor and measure its resistance, with the hope that if they look identical, they are. Once you have that you could look up parts on an electronics supplier's website...
  8. dave9

    Lead acid battery - how long can it be left discharged?

    If you care about battery life you won't discharge it "too" low. It's like asking is it worse to shoot myself in the foot or in the ear. You know it's harmful so just don't do it. If your power needs exceed your battery capacity then you increase your battery capacity. That's the accepted...
  9. dave9

    What should I get for beginning electronics?

    I respectfully disagree. Additional flux works much better. I've done it w/o flux for years then stopped being cheap about it and ultimately it's even cheaper to not waste so much solder just to get enough flux to make a joint flow well. ~ 90% of the time people use too much solder on a joint...
  10. dave9

    I have a Bose Wave system with no audio

    IN1+/- reading is AC or DC? If AC I suppose a gain stage prior to it could cause that, but if DC it looks like something failed prior to the amp chip and fried it.
  11. dave9

    Practical use of voltage divider

    What exactly is this 46V PSU? I wonder if there's a way to modify it to supply less than 40V so you could use your "Step Down Board" but you also didn't mention what it is, if that would solve the 16.9V-ish 10A requirement, or even (just) the 12V so you need to buy one less widget.
  12. dave9

    Home amp fuse bown always

    A common cause of that in audio amps is blown output transistor(s), but could be something else. Is there any chance you can find a schematic or post good high-res pictures of the circuit board? Also look around the circuit board for evidence of overheating, or domed/vented capacitors. I...
  13. dave9

    Thermal fuse help needed..

    I've seen the transistors on those blower controllers fail on other vehicles, think I would just as soon spend the ~ $11USD (£7.46 delivered) it costs for that entire module. I don't know if this part is the exact model your vehicle uses but from the back of the circuit board it looks very...
  14. dave9

    Circuit for the power Amplifier

    and while we're at it, I have this flux capacitor can someone design a car with it? :D
  15. dave9

    I have a Bose Wave system with no audio

    Yes that's a good place to start. Measure for DCV on the VCC pins, and ACV [audio signal, when sound should be playing], between IN1+ and IN1- (for one channel) and between IN2+ and IN2- (2nd channel). If you have both power and signal to it, measure for AVC between OUT1+ and OUT1-, and...
  16. dave9

    Vizio s3851w-d4 power supply schematics

    If the amp board isn't coming out of standby and sending a signal to turn on 24V, even with 24V from an alternate PSU it might not work. It could be that there was nothing wrong with the amp board (including transformer), that it just wasn't getting the power-on signal from a faulty amp board...
  17. dave9

    Vizio s3851w-d4 power supply schematics

    Now that I see the back of the board, it looks like there is a "STBY" (Stand by?) pin which may need a signal for 24V to be supplied.
  18. dave9

    Vizio s3851w-d4 power supply schematics

    So you're stating that you measured power (voltage) coming into the transformer, across the primary coil, but measure none on the 24V output coil? If so, I don't think that will be an easy transformer to find (I could be wrong because internet, lol). It would probably be easier to find a whole...
  19. dave9

    AvMap EPF IV GPS - 12V power - trying to identify damaged diodes (?)

    Maybe this for the 620? https://au.mouser.com/ProductDetail/ON-Semiconductor/NSR0620P2T5G?qs=sGAEpiMZZMtQ8nqTKtFS/MvGseVf8ctf5dFDFHMBZpk= I do think they're diodes, measure them as current capacity rises with size and you need same package footprint (or close enough), compare measurement with...
  20. dave9

    I have a Bose Wave system with no audio

    Driver meaning the speaker itself? If it blew the speaker coil out you can measure for resistance on the speaker terminals, should be single-digit ohms. You can also set a multimeter to 20VAC range and measure for output to the speaker when it should be playing. Does it seem to power up and...
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