Any help matching power dongles to devices?

I’ve got power dongles coming out my arse; something like 30 of 'em. One thing that’s always annoyed me is that far too few manufacturers label their dongles such that you can match them to the devices they power.

I just moved, and though I tried to keep them all paired, my attempts failed in a few cases. The one I’m trying to deal with this particular moment is for a Seagate FreeAgent Pro external drive. I tried the Seagate web site, but they give no details for what voltage and amperage the drive expects, so I’m totally lost.

Does anyone know of any sites that can help with this? Something that helps you match power dongles with their devices by description and/or photos?

Or even just for this Seagate drive?

I can’t help you. I have resorted to using a permanent maker on adapters saying the device they go with.

Yeah, I’m going to get one of those Dymo label makers and do the same, but I still need the info first. I hope someone else can help…

Not to sound condescending, but have you tried actually reading the labels on the power adapters? Most of the ones I have for equipment, especially major brand stuff like Seagate, Sony and others have the brand name imprinted right on them; some even include the model number(s) of the product they’re intended for. This doesn’t help much if you have multiple items from the same manufacturer, but it can help narrow the field.

A message on a Seagate forum makes it sound like the thing takes 12 volts at 2 amps.

But, another messageboard suggests that you need 5 volts at 2 amps.

To start out, try plugging all of your “wall warts” into the drive and ignore all of the ones that don’t fit.

Next, look for any that say they put out 5 volts at 2 amps, or 12 volts at 2 amps, to narrow down the herd. If you’re lucky, you’ll have just one that meets either of those specs, and that should be the one you want. The difference between 5 and 12 volts is substantial to computer hardware, so if you have a 5 volt and a 12 volt option, and they’re the same polarity, try the 5 volt first.

Another option would be to visit your local computer hut and if you ask nicely, they might let you open one up (if the boxes aren’t shrink-wrapped) to see what the specs are.

I found a picture of one - got any that look like it?

If all else fails, replacement wall warts are available for $39.

Strangely, it looks like this drive is meant to be used with a “Y” USB cable and powered by the computer, rather than an external power pack. You’re sure this thing has a power supply? :smiley:

ETA:

Of all the wall warts I have here, only the ones for my IBM Thinkpad or Apple MacBook have the maker’s name on it, or are at least physically distinctive. Everything else is some generic Korean or Taiwanese maker’s name.

Silver Sharpies are wonderful for tagging the things when you get them. The ink won’t pop off like a Dymo tag might.

There’s a forum post on the Seagate website about this (for the regular Freeagent). The moderator says to contact customer support. I’ll remember that the next time I buy a hard drive.

I couldn’t find specs anywhere, either. I’m not used to having this much trouble with it. Good luck.

Of course I’ve examined them. And the ONLY ones of the 30 or so of my power adapters with the product’s manufacturer’s on them are those from Sony. My Seagate drives DO NOT have the Seagate name on them, nor do any of the others (except those from Sony).

All I have to go on in most cases is the power specifications (i.e., voltage and amperage output). The problem is, many of the devices do not indicate what their power requirements are on the product, and some of them not even on their web documentation.

Thanks for your helpful reply.

In this particular case, there are 3 contenders, all with the same size plugs. My voltmeter says all three produce 12 VDC, but the lowest amperage is 4 amps! The others both produce more. That sounds absurd to me, and it makes me wonder if I’m using the meter correctly. I turn the switch to “A” and the red probe to the input marked “10A”. But I’m a software guy, and I doubt my own voltmeter knowledge is good enough (off to the web to learn more…)

In any case, the 4 amp power adapter seems to work fine, with the glow from the top and side white light looking perfectly normal, which I wouldn’t expect to be the case if the power output was too high.

The Silver Sharpie idea sounds good – I’d never seen them before, but now that I know it exists, I’ll find one. Thanks again.

You can’t measure amperage capacity like that; when you do that, you’re essentially putting a dead short (actually about .1 ohms, typically) across the supply and overloading it. Really, it’s not something you can measure at all–it’s a design parameter of the power supply, and should be imprinted on the PS rating label someplace. Your meter’s current mode is to be used to measure the current draw of a load. You use it by breaking one connection to the power supply and use the meter to complete the circuit, if that’s clear.

The current rating of the adapter is a measurement of the maximum current it can supply. You just need to make sure that your hard drive doesn’t need more current than the adapter is rated for. As long as you’re sure you’ve got the right voltage, there shouldn’t be a large risk of damaging your hard drive if you **try **an adapter that can’t source enough current. It may act funny, though, and I wouldn’t recommend doing it for long. You could risk losing data, however.

**Q.E.D. **has established that your current measurements are suspect, so in case you’ve accidentally picked the wrong supply, keep an eye on the hard drive to make sure it’s functioning properly. The 4A adapter may well not be rated for 4A, but it’s a safe bet that it’s not rated for more than that. This page lists some power consumption figures for several different hard drives. Assuming that one of the three adapters you have is the right one, you’ll always be safe using the one that can source the most current; the hard drive will only draw what it needs.

The edit window ran out. I wanted to further explain my statement regarding the possible current limit of the “4A” adapter.

Assuming the impedance of your probe connection was 0.1 Ohms, when you made the short, the adapter would try to source 12V/0.1Ohm = 120A. The best it could manage was 4A, but that doesn’t mean that’s the current rating. The adapter may have built in current limiting circuitry to keep things from kerploding should a short occur, but assume that it’s built to drive less than 4A.

Also, are there any other model numbers printed on the adapter? You could always search on those to find the specs of the adapter itself. Wouldn’t help you as far as knowing if it matches the hard drive, but it would lay the current rating question to rest.

Also, those wall wart adapters tend to be very poorly regulated. If you increase the load beyond its design tolerance, the voltage drops like a stone. If the measured current was 4 A, and the meter impedance is .1 ohm, then the voltage across the meter probe during the measurement was only 0.4 V.

That’s not quite 12 V, is it? :wink:

Hm. I didn’t realize that. I had assumed that they were fairly solid, for no good reason at all.

I’d like to hear how the hard drive has been holding up with the chosen adapter.

Thanks for the info, Q.E.D. I knew I had to be using the meter incorrectly, but it never occurred to me that there was really no right way to use it to measure what I’d hoped to measure. I should stick to software, eh?

Good info, oft. Thanks.

It’s been powered up and connected for most of a couple of days so far, and all seems well.

Now that the holiday weekend is over, I’ll call Seagate Tech Support again and see if they can give me the final word.

The device and the adapter should both have markings indicating the proper voltage and polarity (i.e. tip positive or negative). Check to see which of them match (and have plugs that physically fit).