Tag Archives: amperage

The common post on the Lionel 1025 transformer

Lionel produced several 35- and 45-watt transformers through the years, including the 1010, 1025, 1015, and 1016. Lionel MPC produced a similar 4045 transformer in the 1970s. They’re small, but cheap when you can find them, and can be useful when you string them together with other transformers. The problem is the markings don’t tell you what you need to know in order to do that.

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Fixing an Asus Memopad that will turn on but the battery won’t charge

My son told me one morning that he’d let his tablet charge overnight, but the battery level was at 60%.  I messed around with it, and indeed, it seemed that the battery had lost its ability to charge with the wall charger. Here’s how I fixed it.

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How to replace an AC power cord

A damaged power cord doesn’t have to mean the end of life for a tool or appliance. Power cords are usually replaceable with simple tools and minimal expense. Here’s how to replace an AC power cord.

If you can open up the device, open it up, snip the bad cord off, tie a knot in the replacement cord and splice it onto what’s left of the old cord.

If you can’t open the device, snip the cord off above the defect, splice the replacement cord onto what’s left and insulate it well with heat-shrink tubing.

Here’s how.

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Using a computer power cord on a garbage disposal

When I replace garbage disposals, I prefer to use a power cord rather than hardwire them straight into the wall. The thing is, I don’t like paying $12 for the official power cord, which is chintzy looking and, frankly, looks under spec’ed. Instead, I prefer to use a computer power cord on a garbage disposal.

The label on a 1/3 HP Insinkerator Badger says it’s rated for 5.8 amps at 125 volts. I found a computer power cord in my stash that was rated for 10 amps at 125 volts. It’s overkill, but when it comes to electricity, overkill is good. Best of all, it let me repurpose something I’d already paid for and was probably never going to use.

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Why you need a voltmeter on your train layout

I’ve advocated voltmeters on train layouts before, but I realized something, after checking out a new-to-me Lionel KW transformer: It’s very easy for a vintage transformer to deliver more voltage than you intend, and through no fault of its own.

The “problem” is that transformers step the voltage down on a percentage basis. In the 1950s when they were designed, household voltage was 110 volts. So a transformer designed to deliver a maximum of 20 volts stepped down to 20 from 110. Today, however, it’s not uncommon for the voltage at the outlet to be 115, 120, or even 125 volts. So that maximum throttle of 20 volts is now closer to 22 volts in this day and age, because you can safely assume the source voltage is 10% higher. And the voltage markers on your transformer, which never were all that accurate to begin with, will be even less accurate.

Most postwar Lionel trains are designed to run at 18-20 volts, so if you turn the throttle to the max, you’ll probably overvolt them. The situation gets worse with other makes of trains.

Marx and American Flyer trains run fine off a Lionel transformer, except that they’re designed for a maximum of around 14 volts. So it’s very easy to unintentionally overvolt those trains to 22 volts if you turn a Lionel transformer to the max. They’ll run, but they’ll soon overheat and the windings on the motor armature will burn and short out.

While one venue I won’t mention by name might advocate only using modern transformers, a more practical and sensible approach is to add a $6 AC voltmeter to your setup, to make sure you’re never delivering more than 14 volts to your trains. While you’re at it, you might add a similarly priced AC ammeter to make sure you’re not overloading your transformer either. See my earlier post for instructions on wiring them in.

Measuring the voltage and amperage of your train transformer’s output

Sometimes you want to know how many volts your train transformer is feeding your trains, in order to avoid damaging the motors. And it’s also helpful to know how many amps you’re pulling from your electric train transformer, so you don’t damage the transformer.

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What you need to know to safely replace or substitute AC adapters

AC adapters inevitably break or get lost. That means you have to replace them to get your devices working again. But a lot of people don’t know how to do that safely. Here’s what you need to know when you need to substitute AC adapters.

This is important. Getting it wrong can damage your equipment, the adapter, or both. The damage can be immediate, or it can appear over time.

The specifications for your AC adapter (also not affectionately known as wall warts or power bricks) should be printed on the old one, and hopefully on the device too. If you lost the adapter and the specs aren’t on the device, try a web search on “ac adapter specifications” and the name of the product.

It used to be you could take the device to Radio Shack, and $25 and five minutes later you had a good replacement. Today you might try Batteries Plus for a similar experience. But if you’re willing to do the legwork yourself, often you can find a close-enough match for closer to $10.

So, with all that said, here are the handful of things you need to know when you’re shopping for an AC adapter. The specifications don’t have to match exactly, but you have to know when you can cheat and when you can’t. Continue reading What you need to know to safely replace or substitute AC adapters

The 2wire 1701HG and its dodgy power supply

I picked up a 2wire 1701HG DSL modem/router/WAP this weekend cheap. The power supply (or AC adapter) was missing. Google indicates the factory power supply is really dodgy. A replacement 2wire 1701HG power supply costs anywhere from $13 to $25.

But it turns out the Sony PSP’s AC adapter works fine with the 2wire. Sony’s power supply is common and dirt cheap. Normally I prefer to get higher amperage when buying replacement power supplies, but the connector is a little weird. The PSP box is readily available, so I’ll go with that, at least for a while.

Now I just have to configure the 2wire in such a way that I don’t have to redesign my whole home network… That’s a project for another day. The main thing is getting a quality replacement 2wire 1701HG power supply, so the unit itself will be reliable.

Reviving a laptop

My Micron Transport LT (a rebranded Samsung Sens Pro 680) died on Friday. I wasn’t a happy camper. Just ask my wife.

But it’s working again today, and I learned something along the way.We’d gone out for a while, and when we got back, I sat down at the laptop and noticed Windows was complaining about low battery power. I didn’t think much of it–I just unplugged the AC adapter and plugged it back in, like I usually do when that happens.

Well, about five minutes into my session it died hard. And it wouldn’t power back up, no matter what I tried. Eventually I got the idea to test the AC adapter. I took the adapter to a known-good plug, switched my voltmeter over to DC, touched one lead to the barrel of the plug and one to the tip, and got a whole lot of nothing. I tried it with an AC adapter that I knew worked, and got a reading. Then I noticed the power cord going into the adapter looked just like the adapter for most portable radios. Hoping against hope, I switched the voltmeter to AC, touched it to the leads, and got disappointment.

110 volts.

Google to the rescue. I did a couple of searches and found places selling AC adapters for a Micron LT, but the prices were outrageous. The best price I found was $55, and most places wanted $70 or $75. I didn’t want to sink that much money into a six-year-old laptop–especially when I didn’t know if the AC adapter might have taken something else down with it. Since the laptop had run fine on battery power, I had a pretty good indication it hadn’t, but I didn’t know.

I found one place advertising original Samsung AC adapters for $20. But they were sold out, of course.

A search on the specifications printed on the AC adapter itself–19 volts, 3.15 amps–yielded devices that would work, but again at prices higher than I was willing to pay.

Finally I decided to search Ebay. Searching on "Micron Transport LT" didn’t yield much except some parts laptops, and substituting "MicronPC" and "MPC" didn’t help. All I learned was that a stripped 650 MHz LT with no drives, AC adapter, battery, or extra memory sold for about 50 bucks. That was encouraging. I could Frankenstein an LT back together if I had to.

So I searched on "Samsung Sens Pro 680" instead, and found some joy. Some prices were outrageous. But I found a seller in Hong Kong with original Samsung OEM units. I also found someone in Brooklyn, Laptopspower, with an aftermarket unit. The prices were comparable–around $35. Did I want to buy an identical replacement? Part of me said no–why buy something identical to something that broke? But the little guy on the other shoulder reminded me that the one that broke lasted six years.

Basically the decision came down to Hong Kong vs. Brooklyn. No question a shipment from Brooklyn would arrive faster, all other things being equal. So I took a chance on the aftermarket unit and placed my order on Sunday night.

It arrived today. I’m happy to say it’s bigger and heavier than the original. Remembering previous jobs, I know some sissy-boy executives would complain about that, but if you’re a dumb PC tech like me, you know that the weight of a transformer is a crude measure of its quality. Cheap electronics components weigh less than higher quality components, all else being equal. Besides, I’m burly enough to manage to carry a couple more ounces without grimacing.

Some other things going for the aftermarket unit: It has an indicator light, so you know when it’s getting power. This way I’ll have some warning if and when this one dies, and I’ll know to save my work. That would be worth 30 bucks right there, if I happened to be working on the right thing. And the amperage of this unit is 3.2 amps, not 3.15. That’s not a lot of difference, but more amps is better. The laptop will only draw what it needs, but higher capacity means a cooler-running, longer-lasting unit.

And, as a bonus, I learned that the LT’s CPU is removable and upgradable. Just look for an MPGA Pentium III. The catch is that the fastest chip the LT will take is 800 MHz, and it wasn’t produced in large quantities. An 800 MHz MPGA P3 runs about $80. My 700 MHz chip costs about $30. That’s an expensive 100 MHz upgrade. But it’s nice to know I can get more speed, if I’m willing to throw money at it. It used to be that the only way to get a faster laptop was to buy a new one, after all.

So my LT is back in business again, and I’ve learned something. That can’t be bad.

Replacing wall warts with PC power supplies

I wrote a long, long time ago about my adventures trying to find a wall wart for my old 8-port Netgear dual-speed hub. The other day I stumbled across a novel idea for a replacement.
I won’t rehash how you determine whether a unit is a suitable replacement–read the above link if you’re curious–but suffice it to say a $5 universal adapter from Kmart is fine for my answering machine or my cordless phone and can probably provide the 5 volts my Netgear needs, but my Netgear also needs 3 amps and the universal adapter I keep around can only deliver 20% of that. The beefiest 5v unit I could find at Radio Shack could only deliver 1.5 amps.

A PC power supply delivers 5V and 12V on its hard drive connectors. And PC power supplies deliver plenty of amperage: one of mine will deliver 25 amps on its 5V line, and 10 amps on its 12V line.

In a pinch, I could just obtain a suitable plug barrel that fits my Netgear from Radio Shack, clip the power connector off a dead CPU fan, and solder the plug to the red wire (5 volts) and a black wire (ground), put it in a PC, and use that to run my Netgear hub. The increased power draw would be equivalent to putting three typical PCI cards in the system. Just be sure to wire things right–reverse polarity can kill some devices.

Rather than using one of the PCs I actually use, it would be better to obtain a cheap microATX case, short the green and one of the black wires on the 20-pin motherboard connector with a paper clip, insulate the paper clip with electrical tape, and then wire things up to the drive connectors. Or, for that matter, you could use some of the other leads available on the 20-pin connector if you have a device that needs 3.3 volts (pinout here.) You could also just use a bare ATX power supply with a paper clip connecting the green wire and one of the black wires on the 20-pin motherboard connector, if you’re into the ghetto look.

An AT power supply would also work and it offers the advantage of being really cheap and common (here’s a nice writeup about an AT power supply’s capabilities), but most AT boxes require you to hook up enough 5-volt devices to chew up about 20% of its rating on that power rail before they’ll power up. I have a 200-watt AT power supply that delivers 20 amps on its 5-volt rail, so my 3-watt Netgear hub probably wouldn’t be quite enough on its own. So it might be necessary to either connect an obsolete motherboard to the power supply or connect a 1-ohm resistor between a +5 lead and ground, if you don’t have a plethora of power-hungry 5-volt devices to plug in.

But PC power supplies provide a cheap and commonly available way to replace odd wall warts, or at the very least, to reduce the clutter around the computer room.