Replacement 12 Vdc Adapter

After a recent move, I cannot find two different 115 VAC to 12 VDC power adapters. My experience with laptop PC has shown that there are a LOT of different DC plugs; clearly not interchangeable

Is there a way to determine which DC connectors I need. I have tried emailing each Customer Service, manufacturer of both parts, to no avail.

Reply to
joe
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Ebay? You can usually find cheap ones there by make/model.

Reply to
trader_4

This is just an example of something that might work for you. This exact model might not work for you...I am simply introducing the concept of adapters with multiples plugs. They also have adapters with multiple plugs and multiple voltage outputs.

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Reply to
DerbyDad03

Or

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Reply to
Retired

Yes, everyone should have a universal adapter in the house, thought htis is only 300ma and on Amazon for less money is 1amp iirc and maybe

1.5 or 2 amps. When the adapter for my router adapter stopped working, I ran on a universal one for 2 weeks until I could buy a replacement online, and when that one burned out, I still hadn't put the universal one away, so it only took a minute to plug it in again. I think 300ma is more than enough for the router but not for a laptop. Even 1000 or 2000ma probably isn't, iirc.

Once you figure out which tip fits the laptop, it will help you buy a dedicated adapter, but trader is right. Ebay has them already labeled as to which device it originally powered. That's how I got an exact replacement for my D-Link router model whatever power supply. (However this particular model turns out they tend to be defective and only last 4 years.)

When you click on Find in Store, does it start and never finish?

Before the financial problems radio shack was very expensive for tips. You got two with their universal adapter and it was maybe $5 each for added ones.

Reply to
Micky

Presumably, you mean "barrel connector" plugs. As you say, there are a lot of different DC plugs -- not all are barrel connectors!

Google for the device in question and, with patience, you can usually turn up a reference that will quantify the inner and outer diameters of the center and sleeve connectors.

When looking for a replacement power supply, you will need to know the polarity of the connector (assuming it is DC and not AC) as well as the voltage and current ratings. Most connectors in the US market have center positive polarity. This will be indicated (if you are lucky) on your device probably with a little legend like:

  • ----o)----- -

where the 'o' is representative of the center conductor and the ')' represents the outer sleeve conductor.

Note some devices have a third center *pin* (literally needle-like) that allows the device to talk to a bit of electronics in the power supply to, among other things, identify the power supply as the "correct" power supply for the device (so, an HP power supply might not work on a Dell product -- even though they have the same electrical specifications).

You can purchase "universal" chargers -- but typically only in smaller power ratings (e.g., I have a device that has a 200W power supply "brick"). You can also purchase adapters that will convert between connector sizes (though usually not alter polarity). While they claim to be universal, often they only address the most common types/sizes of connectors. (I have a large assortment of these "tips" and keep encountering new varieties!)

The "kids" at Radio Shack will have a keyring with all sorts of these plugs on it so they can tell you which (of *their*) plugs are compatible with your device: "Let's try this one... nope! How about that one? Nope! OK, maybe this other one...?"

Once you have the "mating plug", it can be "quantified" by measuring the outer diameter (caliper being your friend). And, the inner bore diameter (a set of twist drill bits are invaluable for this!). They are typically metric sizes -- e.g., 5.5mm sleeve is a common size.

Note that the correct connector will fit snugly -- it won't wobble side to side after mated (if you use a plug with an over-sized center bore, the connector will appear to fit but not snugly)

Reply to
Don Y

What makes and models are they?

Reply to
Micky

I am trying to replace the AC -> DC adaptor for

1: Cavalry dual external hard drive module model EN-CAHdD2B-D 2 .Black Decker 3.6 v dc Pivot Drive (screwdriver) model PD40LG type

As another suggested, I will check ebay for options

A sincere thansk, to the many responders - much appreciated

Reply to
joe
[snip]

I used to have a Dell laptop like that. IIRC, an adapter without that chip would run the laptop but it wouldn't charge.

I have a universal laptop adapter (19V 4.74A), with 6 tips. 5 are different size round connectors, the 6th is shaped somewhat like a USB connector (I have a laptop, Lenovo Yoga 2, that uses that.

[snip]
Reply to
Mark Lloyd

I had a universal laptop adapter too, from a big name maker, that also worked with cigarette lighters and the jacks on airplanes. But the tip wasn't right for mine. So I made my own adapter, a jack connected to the proper plug. It was only after I did that theat I figured out that something in the tip told the power supply what voltage to put out, and mine was still putting out a couple volts too little for my laptop.

And the whole thing was silly anyhow since I like to look out the window when i'm in an airplane, and airplanes are moving away from the special jack to 110vac jacks.

Reply to
Micky

It is best to get the real adapter for a lap top and if it has a few miles on it they are usually cheap on Ebay.

Reply to
gfretwell

IIRC, Dell and HP bricks don't play nice together.

I typically use my "universal" adapters for oddball devices that I've rescued (or, am *thinking* about rescuing). They typically don't have the same sort of hefty power requirements that laptops do -- but tend to have a wider variety of voltages and connector configurations!

Laptops tend to have their power supplies "nearby" (when rescued). But, the oddball bits of kit (label makers, iPod docks, external disk drives, etc.) seem like their power supplies are often misplaced.

With a universal adapter, I can see if the device *will* work before setting out to find a suitable power supply to "allocate" to it.

Reply to
Don Y

MOST power supplies with a third pin use that third pin to measure battery temperature. No pin means the battery is hot? and it won't charge. Many laptops require a 18 or 19 volt power supply to charge the battery - yet will run fine on 12 volts, while the actual battery voltage is 11.1 volts (3 lithium cells of 3.7 volts eash) which requires 12.6 volts to chargew.

Reply to
clare

The Power supplies that I've examined have a serial EEPROM connected to the third lead. The PCB labels that lead as "ID".

The *laptop* controls the charging profile, not the power supply. The power supply merely indicates how much "power" it can deliver to the laptop -- which the laptop can then redirect to the battery pack.

Note the number of connections between the battery pack and the laptop (vs. the two -- or three -- between the power supply and the laptop)

Having no center pin means the laptop is "unsure" of the characteristics of the power supply.

I've not examined the actual protocol to see if it encodes capabilities in some manner that would allow the laptop to recognize a 90W supply as LESS capable than a 200W supply -- yet MORE capable than a 65W supply.

Or, if the "ID" simply says "I am model #12345" or even "I am genuine Dell"

This information is especially significant for laptops that support a second battery.

Reply to
Don Y

If it were the same voltage, it would have worked. And it might even have worked at 2 volts lower than ideal???, not for recharging but while being used??? But I didn't think of that then.

I didnt' think there was any correlation between the exact tip and the voltage. That any and every tip might be used for every voltage. But maybe there is when it comes to laptops???? For one thing I thought just about every tip was used for 6 volts some of the time.

If there is a correlation, a chart that listed it would be handy, but a quick search didn't find one.

It was expensive, about $10**, considering it was only a tip and I also rarely fly, and I didn't think to look on ebay***. I was going to give it to my friend whose laptop fit the tip I had. He died and it looks like his brother, who came from out of town and was in a hurry, just gave everything to Goodwill. I would have enjoyed having some of his tools, for sentimental reasons.

But maybe I never got around to giving him the power supply. If so, it will turn up here.

**It was an open package at a computer store, and quite cheap, and it didn't occur to me that the target market, businessmen, aren't going to quibble about the price of a tip. I wouldn't either in their shoes, expected to get work done on the plane, but for me it was more like buying a raccoon tail for my car's radio antenna, just a fun accessory and not something I actually need. ***With a quick look, I can't even remind myself of the brandname, but if you want to know what sort of electricity your seat has, if any,
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has all kinds of details about your plane and seat, including good seat/bad seat, TV, where the wings are, where the bathrooms and galleys are, including based only on your**** airline and flight number. The 747 I picked at random had house current at every seat. Unless you never fly, the site is really worth looking at, at least once. ****When I was in Guatemala 45 years ago, I was talking to a 15-year old girl and I made reference to my bank. And she giggled, and that's when I realized that there at least, or maybe in Spanish almost everywhere, it wouldn't be called my bank unless I owned it.
Reply to
Micky

I just saw, yesterday at a hamfest for $20, a universal wall and car laptop powersupply, once sold by RadioShack, NIB, and because of this thread, I wanted to buy it, but I controlled myself.

16v/19V., 90 watts

Here it is. $100 with 8 tips.

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Here's the same thing used with no tips for $14.

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or beat up NIB with all the tips I suppose for $21.
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Reply to
Micky

Ah, so I was right! I wish I'd realized this 5 years ago, though in practice it made no difference.

Reply to
Micky

Both of these are a lot smaller than a laptop and will I think run off of a 1amp universal. I meant to look downstairs how big miine are. I think they are 500 or 1000ma and I was thinking of buying twice as big.

Reply to
Micky

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