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  1. S

    ic's

    I'd consider all IC's static sensitive, it's just a matter of how tolerate. The most well-known ESD sensitive family are CMOS (Complementary Metal Oxide Semiconductor), but there are many others now. You really should use careful handling with all IC's. Did something happen in particular in...
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    PCB Tracing

    What am I missing? If you've got an actual short to ground, an ohmeter oughtta get you there pretty quick. If you're really having a problem with this, disconnect any connectors going to the board to make sure you HAVE the correct board. Do a visual inspection for the damaged component...
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    What is this part? (from an old climate control circuit)

    They're called 'Power Resistors', readily available from electronics supply stores. The resistance value and tolerance are written on them: 50 Ohms at 10% tolerance Can't see for sure, but the small one looks like 5 ohms at 10% tolerance. These are an old (dependable) style, but you should...
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    ULN2803A losing voltage

    Don't know your experience level. ARE your 5V relay coils, 500mA draw or less, as called for in your circuit? (If the current draw is excessive, it'll screw you up). I assume you know the ULN2803A is a transistor array, you lose .7v right there. If you're using the SIP (Single In-line...
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    How To Prevent Electrical Noise From A Motor?

    Ohhhh. Radio Shack and Olsen used to sell these things cheap before the improvements in vehicle electronics. All I remember about them was they were tuned to the basic frequency of the vehicle's electrical system. I don't know if this is a home project, or if you have a commercially built...
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    weird question... i think

    First off, don't short the output jacks of your amp with the antenna wire. Antenna are designed to transmit or receive on higher radio frequencies. Amplifier outputs are designed to output lower audio frequencies. Theoretically I suppose and antenna connected to an amp output jack would be...
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    How To Prevent Electrical Noise From A Motor?

    We need a little more information. Is this noise because the motor is vibrating? Should you use rubber isolators? Is the noise inside the motor? Do you have bad bearings? Is the noise mechanical or electrical? Is the noise electrical because you're overloading it? Is the noise mechanical...
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    Home/Office Thermostat Control From Internet

    I remember some guy on this site asking several times about finding a way to adjust his office thermostat from home, before he left for work in the morning. Just got my latest 'Nuts & Volts' magazine. Page number 34 starts a multi-part article: 'Web Browser Control of Your Home Thermostat' by...
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    Strange connector needed

    Maybe somebody will be able to ID the connector for you. When I run into a problem like this, I consider actually replacing the plug and socket with another connector that mate. If you go that route, take a good look at the socket, it's retainer, outside diameter size, depth into the laptop...
  10. S

    Ferric chloride

    I don't know what you're doing, but you always use distilled water when mixing chemicals, because you don't know what-all is in tap water. (Chemicals, minerals, whatever).
  11. S

    Strange connector needed

    So far, in one catalog, I found some: XLR-Style Audio connectors that look like they might work. I'll keep looking. Google XLR connectors, and see if one of those might work. (I didn't check for pin configurations, so they might not, but it's worth a look) Your plug really reminds me of a...
  12. S

    Strange connector needed

    I've seen similar connectors. I realize the equipment manufacturer has the replacement at a high cost. It may have been made specifically for your equipment, but do you see any manufacturer logo or information on the plug itself? The 'key', the groove in the top of the connector has been...
  13. S

    What are these components?

    Don't know. The circled 'W' is probably the Westinghouse logo,.... That might get you started.
  14. S

    For Sale: Values on old test equipment?

    daddles is right. Sounds like you want to try to sell some gear. Check prices on ebay to see what each piece is worth. Bear in mind replacement parts are pretty expensive. Functioning instruments will command much higher prices than non-functioning ones. (If you can fix them before trying...
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    Need help identifying component!!

    Whoa. That's not a cap, it's a MOV (Metal Oxide Varistor). 275V, 4.5KA. It's purpose is to absorb transient voltage spikes, to protect the circuit. You can probably find a data sheet on the device 275L20, ... the 0409 is the date code, manufacutured in 2004, 9th week of manufacture). It's...
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    Speaker Hiss Help

    Start from the beginning. Check your power cords to all the different devices. If you've got a 3-prong adapter in there somewhere, you might have to turn a plug around, so all the components are on the same neutral wire. Check all your other wires. Do you have a power cord wrapped-up near any...
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    headphone repair

    Oh, you're probably a newbie at this. What you're going to find, if you try this, is that to save money in manufacturing, and for flexibility of the cable: are VERY fine diameter wires, wrapped around a string. You need to look at the wire, which will be one unpainted common wire, and two...
  18. S

    headphone repair

    The problem is the cable. Probably at one end, where it connects to the connector, or the headphone. Plug the headset in, and wiggle the cable at each end, to find the problem. When I find exactly where the wire intermittent is, I cut back the cable past that point and resolder the wire to...
  19. S

    potentiometer making weird noise

    I'm thinking about this, so I'll mention it for you to consider. It sounds like the AC hum is being induced into your circuit. Are you working around a flourescent light, or some other electronically noisy device while you're working on this? The power outlet tied to some other device that...
  20. S

    potentiometer making weird noise

    Nobody pays much attention to pot construction these days, but in audio circuits, the TYPE of pot might be an issue. They're not all carbon wafers these days, there are several different types of construction. In Johnsonmusicstudios case, I'm thinking davelectronic's explaination makes more...
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