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  1. dave9

    Question CR2032 battery

    ^ I mean Duracell alkaline. The only NiMH I've ever had leak were some no-name brand that I bought as NOS surplus, which were already crusty inside the sealed blister pack. I got a refund for those. NiMH, I have many AA Tenergy Centura made in China, in regular use and haven't had any...
  2. dave9

    Question CR2032 battery

    Hmm, I can't say that I have a lot (or any that I can recall) products with multiple CR2032 in series, but of the several things with a single CR2032, i have never had one leak, even motherboards now over 20 years old with the original battery still in them. Granted, I don't check those daily...
  3. dave9

    COVID-19 Human to Human 'Proximity' Logger

    It seems like an intrusive waste of time. It depends on both parties (or really, everyone) having the sensor which isn't going to happen unless government or an employer is mandating it. Plus, there is no assurance that you can nail down that short of a range without line of sight measurement...
  4. dave9

    Searching for Solder

    Hmm. The lead was in the ground, in the environment, then we mined it up and with it in lots of things, there is less lead in the environment, and the great danger is we might throw it away so it is in the ground. Makes perfect sense.
  5. dave9

    Searching for Solder

    You might get it as soon from an electronics supplier like Digikey, but either way, what size roll? General purpose solder, I'd get a pound at a time, and a major brand. Life is too short for generic solder. ;) https://www.amazon.com/Kester-Solder-24-6040-0027-Activated-Rosin/dp/B0032UVNJW...
  6. dave9

    Ebike battery

    ^ Underestimating the complexity, is why you're likely to have a fire, and personal injury. I can say a car is "just an engine, wheels, and a cabin" but we both know the devil is in the details. I did not mean an electric scooter or motorcycle, the exact opposite, a used gasoline engine...
  7. dave9

    Ebike battery

    If you reap any cost savings, you'll end up paying for it 10X over in time and frustration, or suffer longevity in lifespan or travel distance. Merely adding up # of cells needed in a battery, is nothing compared to assembling a pack, using a spot welder, into an appropriate size...
  8. dave9

    Need help with vacuum repair (TBT3V1P1)

    Okay, but then it seems like a coincidence that you have a second problem. If the switch to turn it on is in the head, then power is going through it when it shouldn't, so I suspect a switch failure. Use a multimeter to check whether the switch is closed circuit when it should be off, and take...
  9. dave9

    Need help with vacuum repair (TBT3V1P1)

    Probably reconnected to the wrong spot. Look at the circuit board and trace it from the brush button, probably one side has constant power from the battery (when the main suction motor is on?), so trace the other switched contact till you find a place to solder the output wire to the brush motor.
  10. dave9

    Technics SL-PD827 Problem

    Open it and inspect the mechanism. Certainly you should check the belt, if one is present, but I would've guessed it was gear drive. Lube anything that moves, but of course not where the lube would fling off onto the lens or CD.
  11. dave9

    Increase 12 VAC

    Did you measure the 14.8VAC loaded (as input with the regulator board attached and powering the intercom) or unloaded, with nothing attached? I suspect you're suffering too much voltage drop. Is your 12VAC supply at the house end, so instead of supplying high mains voltage at the gate to it...
  12. dave9

    TDA2030a Amplifier I.C. Specs

    Are you intending to use TDA2030a for a specific purpose?
  13. dave9

    Communication Circuit In Inverter AC PCB Board

    I'm going to go out on a limb here and suggest that what you are stating is incorrect. It looks like you have just pictured a power supply board that has nothing to do with indoor, outdoor unit communication, unless they happened to integrate that feature onto the PSU board, which I would...
  14. dave9

    Parts needed?

    On the one hand you make no mention of whether he is consciously aware he is doing this or if the redness bothers him, or his parents, or just you, or if you have discussed this with them and they are ALL receptive to this type of solution. On the other hand, this is trying to treat the...
  15. dave9

    Stupid question about Resistors

    Often a board has what is considered a top, bottom, left, and right side, whether it is due to how the designer saw it in the layout program, or how the silkscreen text is oriented. It is easier to read the resistor values later if you orient them all so they read correctly from left to right...
  16. dave9

    Questions many hours for recharge battery lithium via USB cable connected in Hub USB

    ^ That does not look like a link or more info. Maybe there is nothing more at that link, or maybe there is enough to find other sources for the product that have more specs or even someone who has done a teardown. The more time you have everyone spend on this, even less it makes sense to...
  17. dave9

    Questions many hours for recharge battery lithium via USB cable connected in Hub USB

    Link to this hub on the seller's website or provide more info. Without more info, and possibly even then, there is nothing more to say except that it does not do the job and nothing is reasonable to do to it, considering how inexpensive that standalone AC-DC wall wart type USB chargers are...
  18. dave9

    LM338 Voltage and Power Questions

    It's not confusing really, if you want it simple then all you have to do is use the center tap to get 12V if you don't want to consider the other wiring scheme I mentioned. That still seems a better option to not waste over half the power as heat, compared to taking the full 24VAC into the...
  19. dave9

    LM338 Voltage and Power Questions

    ^ I'm not suggesting it would do harm but rather, for 110VAC it runs the two primaries in parallel to get 4A output. If using 110VAC with the two primaries in series, shouldn't that result in 1/4, (or 1/8th?) the current? I don't know. This wouldn't be a hard thing to measure and change...
  20. dave9

    LM338 Voltage and Power Questions

    There is no current reduction doing that, AFAIK. You'd still have 4A @12VAC. However, I overlooked something. Since you bought from MPJA, I assume you're in the US, and therefore using 110VAC mains? If so, take a look at the wiring diagram on MPJA (included below). You might be able to wire...
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