Frankenstein's Components.

Discussion in 'General Electronics Discussion' started by (*steve*), Nov 27, 2012.

  1. (*steve*)

    bigone5500

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    Stupid spammers.....
     
    bigone5500, Jan 10, 2017
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    Johan_Ha

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    Our school has moved from an old building and the building is about to be closed and demolished. A lot of old electronics was left there, stuff we didn't use anymore.
    From two wire telephones I picked the piezo mics and speakers. From one matrix printer I picked two stepper motors and a dented belt with its dented wheels. I also have two identical laser printers with worn out drums. They probably contain one stepper motor each. And a lot of components, together more worth than the 25 € a working printer of same model is worth on the 2nd hand market.

    The step motors might turn into robot arms powered by two car accumulators and controlled by Microbits.
     
    Johan_Ha, May 6, 2017
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    Tha fios agaibh

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    My youngest was complaining that his Power wheels battery operated car wasn't fast enough for him.

    I added a second 12v battery in its storage compartment and wired in a relay that switches it from 12v to 24v when a button is pushed. I didn't want it full 24v starting out for fear the excessive torque would strip the gears. The way it's wired now; he has to first hold down the accelerater pedal and once the car is moving he can push his "turbo" button and the car speeds up dramatically.

    The car is twice as fast and my boy is thrilled.
     
    Tha fios agaibh, Aug 29, 2017
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    Braeden Hamson

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    You can get lithium cells out of laptop batteries (no surprize) if you go to Goodwill they sometimes have stacks of them.
     
    Braeden Hamson, Aug 30, 2017
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    mr fixit

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    Back in the 70's and 80's I was a mainframe Engineer. One of the benefits of that is the knowledge that back in those days, mainframes were expensive, so manufacturers could use high precision, expensive fittings, castings and hardware. I used to frequent sales and auctions, knowing what hardware was in what pieces of kit.
    Mag tape drives (reel to reel) and the old "washing machine" sized disc drives had to be precision built because the electronics used in them was so crude.
    Huge chunks of aluminium for the base, heaps of high-tensile big Allen bolts, Smaller phillips screws with integrated washers, domed nuts (brass), all chrome plated of course. Look great on modern kit front panels or under the hood of your car.
    Many very handy brackets and cases, panels (usually aluminium but sometime stainless steel.
    Lord alone knows how much this stuff would cost to make today!
    I remember one power supply in particular that supplied the -5 volts for the core memory in a mainframe.
    The memory was 65K per plane - 1 megabyte in total (cost was $1 per byte, by the way. Do the maths).
    But the PSU was capable of supplying -5 volts at 1200 Amps. The output stage was 600 2N3055's in parallel.
    Each had a .1 Ohm emitter resister. Each was handling 2 Amps. Very relaxed running for a 2N3055.
    One of my maintenance tasks was to check for dud 2N3055's. Check the emitter resister voltage on EACH transistor (600 of them..). Any that didn't show a voltage meant that transistor was open circuit. None ever showed up a short circuited. Have a guess why...
    Get one of those PSU's and you would have a lifetime supply of 2N3055's!
    Even the humble latches and hinges. Not the cad plated steel mounted with rivets or maybe self tapers.
    These used chrome plated piano hinges, secured with dozens of chrome plated brass countersunk bolts and nuts.
    Each had a specified torque setting, and was to be secured with a dab of locktite!
     
    mr fixit, Dec 3, 2017
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    kellys_eye

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    As much as I've been trying to, finding old equipment for re-purposing has been a sort of hobby of mine for years. In the current economic climate it's been difficult to get stuff as anyone/everyone now recognises the inherent value of such stuff, even if they themselves can't find an outlet for it.

    Doesn't stop me trying though! Older relatives and friends often come up trumps with antique stuff but more often than not that turns out to be ripe for restoration rather than re-purposing (nothing wrong in that, some stuff is great after being fixed up and there's a busy hobby/market in that anyway).

    But, now that I've relocated to the sticks I have no opportunity to dumpster-dive or scrounge stuff but I still get people locally dropping off old stuff now that they know I'm geekish that way!
     
    kellys_eye, Dec 3, 2017
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    FuZZ1L0G1C

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    Over past decades, have stripped down old dot-matrix printers for gearing and stepper-motors, CD / DVD players, Rare-earth magnets!! :)) from a microwave oven, (discharged HV cap using HT gloves & damp salt-soaked sponge).
    Dozens of 6VDC relay boards from factory sale, two huge caps rated 400WVDC 6H8 (bargain bin at electronics component store), nixie tubes, several old 350W>400W desktop PSU's....
    At least two 100L plastic storage bins full of stuff.
    Recently bought a heap of IC's, resistor packs and 3.9v zeners from a self-employed engineer/tech who emigrated to UK, so sold off all stock. Also sold me 2 CRO scopes, one which works great, other I still need to fault-find / repair.
     
    FuZZ1L0G1C, Dec 3, 2017
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    poor mystic

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    I accidentally discovered a method of raising the resistance of metal-film resistors while building a prop for a TV advertisement.
    I tried to set off a little bit of flash powder with a low voltage and a low resistance element in the form of a 100 Ohm metal film resistor, but found that the charge didn't go off. Investigations were protracted, but showed that whatever value of metal-film resistor I used, the resistance would rise to a value at which it would no longer get hot.
    My explanation for the resistance change is that the resistance of the component is determined by the amount of metal oxide in the coating. When the component got hot, the oxidizer in the flash powder was heated and released oxygen, which burnt the component and so altered its resistance, reducing the current and power dissipated in the component until the oxidizer was no longer dissociated by the heat.
    So a resistor, packed in oxidizer, with a power source, could be used to record the maximum voltage supplied by the power source. Or, using a variable voltage supply and a stock of 1 Ohm resistors, any resistance can be achieved up to a limit imposed by the maximum voltage of the supply.
     
    poor mystic, May 28, 2018
    #48
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    Sunnysky

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    In the mid 80's I spent 500 bucks on a "mineral THerapy lamp" that looked like it cost 20 bucks to make but the Hollistic convention salesman Dr Li showed me the photographs of healing just about anything, THe japanese call it FIR therapy which is the same and means far Infrared known for having a deeper skin depth and therefore more therapeutic on the inside than a toaster heater or tungsten IR lamp. I found it worked for my G/F's arthritis any boils on my leg or back pain or reduced pain in elders knees. Nowever every CHinese Accupuncture doctor has the "Happy Lamp" THe japanese also sell reflective underwear to reflect the far infrared we humans naturally emit. Which also supports the theory why two people who sleep close together live longer.

    But my favorite Frankenstein Tool I've used a couple times in coldest winter days when I left a door light on or the engine was stiff and only 30% capacity at -30'C. A toaster in series the line and a power diode in snow with Neutral ( near 0V) to the battery -ve terminal all connected with jumpers and start the car up in 10 minutes or so from a dead battery. Then add a bagel in the toaster, at half power drink coffee when done.. start car.

    BTW metal film resistors make crappy igniters low noise but low power PTC's
    try wirewound or nichrome for squid igniters or maybe carbon. But a wooden match wrapped in nichrome wire was pretty reliable.

    In the 70's it was common practice to turn 10% disc ceramic caps into 0.1% with a file or sandpaper to tune an LC resonator in the lab.

    I also have an early 100W LED array from about 10 years ago, the size of a silver dollar on MCPCB that works on 12V great from an old PC PSU with a CPU heatsink and microfan. It hurts to look at it more than a blink which makes it about as large as the sun in the sky and as bright during midday, at arms length or 3m above the ground.
     
    Last edited: May 28, 2018
    Sunnysky, May 28, 2018
    #49
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    FuZZ1L0G1C

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    More of an unusual use for a product than a 'Frakenstein' component:
    Recently been upgrading my home PCB manufacturing setup, I shopped around for a better heating alternative to my Salton Hot-Tray for keeping Ferric Chloride at working temperature.
    A pet-products store near us sells "Reptile-Cage" warmer pads, size I bought was 300 x 200 mm at 100 W 220 VAC.
    100W is great, as it gets warm, under the tank, without boiling the etchant.
    The only drawback is the mains voltage near potential spills, waterproof ability unknown..
    Now searching for 12V DC or so...
     
    FuZZ1L0G1C, Jun 6, 2018
    #50
  11. (*steve*)

    FuZZ1L0G1C

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    Frankenstein's-components -- Old coils:
    Several years ago, while purchasing components at our electronic components retailer, I noticed dozens of coils and solenoids (some vintage) on a mid-floor display table.
    As they were fairly cheap (stock clearance), I bought a whole lot of various sizes and impedances, without a definite purpose in mind.
    By measuring the impendance with a DMM or LCR bridge, many experimental hours of fun designing / experimenting with crossover networks, audio filters and electromagnets were had.
    Example: An 8 Volts DC buzzer coil has a low DC resistance, due to thick enameled magnet wire, so works great for Bass / Sub driver unit, damping the highs.
    A 500 V AC elevator board relay's cylindrical coil is a great source of ultra-fine (hair-thin) enamelled copper wire, guessing about 40-50 gauge.
    A relay or solenoid coil can be the 'lifter' in a magnetic broken-beam Levitator circuit desk-toy.
     
    FuZZ1L0G1C, Jun 13, 2018
    #51
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