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  1. S

    Unknown IC

    Got some IC's marked: HOA9026A /C 7800 303XA 27014 Found a vague reference as possible equivalent to LM143H Anybody know anything about this IC? I'd like to know what it is, or if it actually IS equivalent to the LM143H.
  2. S

    IHome speaker cable

    Ok davenn, I'm going to give that method a shot next time. I always just laid the iron on the side of the wire, must be where I made my mistake. Thanks for the insight.
  3. S

    Quest smoke alarm randomly chirping

    Just check the date of manufacture on the box when you buy them. Don't buy one that's been sitting on the store shelf for several years. Can you tie the chirping to some event? A motor, air conditioner or heater cycling-on (you said it's wired into your house wiring) Maybe a power bump...
  4. S

    IHome speaker cable

    Yeah, I use an exacto-knife to get the laquer off the wires, so I can resolder them. I've tried and tried to solder through the laquer like davenn said, but never with success. Maybe the coating is getting better these days. Also, because of the cheap insulation these days, the excessive heat...
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    What is a subtitution for this transistor

    I've checked all the old Texas Instruments data books I've got. The GP number must be some proprietary part number. Frankly, I don't think there were all that many TO-3 packaged transistor types made in the mid 1960's, so there can't be that many different types you'd have to figure-out it...
  6. S

    Which motor

    You'll probably need gearing to mate with a motor that will do the job. Check into stepper-type motors, that are high-torque, already-geared assemblies that will give you the torque and speed you need.
  7. S

    Electrolytic Capacitor - Settling Time

    I don't know what else is out there, but I use a Sencor Z-Meter to check for capacitor leakage. If it's a single cap, maybe you should just replace it, and see if that solves your problem.
  8. S

    Quest smoke alarm randomly chirping

    My experience if it's not the battery, is the detector itself. They have a limited life-span, as pointed-out by KJ6EAD. I bought a lot of them at the same time, they all died within 4 months of one another. Even though you replaced the alarm, if the replacement was as old as the original...
  9. S

    sony reciever amp str-d1015

    I concur. It's not the receiver, it's your speakers. Wrong impedance speakers, or you're wiring multiple speakers in parallel (which changes the impedance the receiver 'sees'), or if you don't believe any of that, check to make sure your speaker wires are large enough gauge wire to handle...
  10. S

    ultrasonic cleaner, help needed

    Another thing to consider, is the possiblility that the two variable inductors are each running 1/2 of your transducers. I can't think of a reason why two would be needed in a single circuit to run all the transducers. When they built your cleaner, the engineers had already determined the...
  11. S

    Furnace motherboard

    I believe they know there's a problem with their design, because it sounds like they're familiar with the problem you reported to them. Possibly, the next time you lose the board, they'll have engineered the fix into the new replacement. Don't mean to sound insensitive about that, but...
  12. S

    Why are 0 Ohm resistances connected in a PCB?

    I've worked a lot of old Hewlett Packard test and measurement instruments. The practical effect of the zero ohm resistors, which are heavily used in old HP gear, are as fuses to protect the circuit on the next board, from a circuit problem on another board. Somebody may offer you a more...
  13. S

    Furnace motherboard

    Pointless to add a surge protection device, the GFI will trip long before the surge suppressor had a chance to work. You've already talked to the manufacturer, try again, and ask if they have any recommendations. It was a little startling to hear them say your controller died before they...
  14. S

    low voltage ,circuit problem

    Difficult to do with the modem itself. It's designed to operate at the voltage printed on it. DC to DC (voltage) converter might work. Why can't you use an adapter to obtain the voltage you need?
  15. S

    Newbie

    Look around for project paperback books in the area of electronics you're interested in. There are a lot of them out there. Google the type of circuit function that interests you, and you should find a lot of 'hits'.
  16. S

    Plz explain me behaviour of Speaker

    You also need to pay attention to the impedance of the speaker you're using. Does your circuit call for a conventional 8-Ohm impedance speaker, or something else?
  17. S

    Help with a toy

    If the battery case is stand-alone, I'd just replace it with a new battery holder. The size 'D' batteries will have more current to run your train, than the smaller 9Volts. If you have to use this holder, you'll have to get rid of all the rust, and make sure the wiring to the rusted contacts...
  18. S

    Furnace motherboard

    Hard to tell. It's possible the board got wet before you got it (might have been stored outside in the rain by installation company). Or stored in high humidity environment. When they manufacture boards, they wave-solder them, then run them through a bath to remove any flux. But I doubt that's...
  19. S

    ultrasonic cleaner, help needed

    Sounds like tunable inductors for your transducers. With no documentation, you're doing what I'd do: Tune the transducers for what you'd expect to be optimum performance while ensuring your current flow isn't excessive (excessive heating of the transducers). They were probably tuned at the...
  20. S

    Power Supply Loading

    A power tool adapter probably outputs a constant 12 or 14VDC. The adjustment would be for very minor voltage adjustment near that voltage. (Not a 0 to 14VDC range) Typically, unloaded outputs would read a little higher than 'normal' (loaded) voltage. When you put your load on the output, you...
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