Help me not blow up my gear

June 14, 2008 7:45 PM

I need to work out which of my DC adapters powers my devices - I don't want to damage anything.

I have the Western Digital My Book 1 TB and I have the FESV AMP-60 mobile power thingummy. I also have cable clutter. So I untangled everything and fed it all nicely round the back of my desk and ... oh dear.

One power brick is from Channel Well Technology and says that its output is 19v - 3.16 amp.

The other says that its made by HONOR and its output is 12v - 2.0amp.

The tips are the same, which is the confusing factor. My gut instinct is that the external drive will want the 12v brick and the mobile power supply the 19v brick.

Could some less electrically confused people help me here before I destroy my electrical gear?

posted by chairish to Computers & Internet (13 answers total)

Can you look at the back of your devices, near the power jack? Usually there's a legend there that tells you the voltage and polarity of the power supply required. If not there, try looking for a label on the underside of the device. If you still don't know, I'd say your guess is almost definitely right, I doubt your external drive runs on 19v, so it most likely takes the 12v.
posted by DecemberBoy at 7:52 PM on June 14, 2008

Response by poster: Thanks DecemberBoy but been there done that. No such luck in either case.
posted by chairish at 7:53 PM on June 14, 2008

Well, the site for the power supply you linked to says (http://www.fesv.com.sg/productAMP60tech.asp):

Supports multiple voltages
( Select from 4V, 5V, 7.5V, 9V, 12V, 14V, 16V to ***19V*** )

(emphasis mine)

And I've never ever ever heard of a modern Hard Disk which took more than 12 Volts, so.. yeah.
posted by blenderfish at 7:59 PM on June 14, 2008

The replacement power supply at (http://www.westerndigital.com/en/products/accessories.asp?ProdID=247) is listed as "24 Watts." Which, and I doubt this is coincidence, is 12v * 2.0amps.
So, further evidence that the MyBook goes with the 12v supply.

[SERIOUSLY, what the hell is wrong with these companies that they wont list basic electrical characteristics of their devices on the internet or on the devices themselves! What the hell, WD, and people from wherever .sg is?]

..and, of course, even though I am a random guy mouthing off on the internet, I'm not your random guy mouthing off the internet, so I can't be responsible when you light your hair on fire, etc. :)
posted by blenderfish at 8:13 PM on June 14, 2008

(by way of clarification, 24 Watts could be 12v * 2.0 amps. It could also be 1v * 24 amps, or 24 V * 1 amp, but NOT 19v * 3.16 amps (that would be 60 Watts.)

Also makes since that a charger would need more power.
posted by blenderfish at 8:25 PM on June 14, 2008

Here's an image of the Western Digital My Book 1 TB with a power supply. Does that help?
posted by bigmusic at 9:43 PM on June 14, 2008

And here's another one.
posted by bigmusic at 9:46 PM on June 14, 2008

And here is the power supply that WD is selling as a replacement.
posted by bigmusic at 9:54 PM on June 14, 2008

I don't think you can damage your equipment with a temporary undervolt, so plug in the 12v adapter to what you think it goes to, and see if it works. Something that needs 19v won't run on 12, so if it turns on, you've solved the problem.
posted by hwyengr at 9:00 AM on June 15, 2008

Response by poster: Thank you all for your help. I have plugged in the mobile power with the 19v charger and overnight it has charged. Then, I plugged in the external hard drive and it is happily exchanging files with my laptop.

For those people that had pictures. The power supply looks quite different. It has a 'brick' transformer in the middle. I am in New Zealand - 240v - which might account for the difference.
posted by chairish at 12:49 PM on June 15, 2008

Something that needs 19v won't run on 12

Unless it's something like a battery charger, which possibly has a variable voltage regulator, alongside control circuitry that is independently regulated and runs at low voltage (5 or 3.3 or less,) in which case it might appear work fine until you try to charge something which needs >12V. I would hope there would be a graceful failure mode in that case, but I'm not sure that I would want to find out.
posted by blenderfish at 12:18 PM on June 16, 2008

Here is the AskMe for the last time I noticed this kind of question.

I don't think you can damage your equipment with a temporary undervolt,

Well, it is very, very unlikely, but I'm pretty sure it is actually possible...

Anyway.. It is overwhelmingly likely that the external drive uses the 12V brick. The drive inside is just a standard desktop (3.5") or laptop (2.5") hard drive, and they use 12V power. Also, here is a discussion about another MyBook model pointing strongly in the 12V direction.
posted by Chuckles at 4:21 PM on June 16, 2008

Also.. The search I did was "MyBook power adapter specification", and an ebay seller confirming the speculation.

I find it completely hilarious, but also a little depressing, that this AMP-60 device relies on companies printing input power specifications on their gear, yet doesn't do so itself. From the user guide:

Adjusting the Voltage Level

1. Locate the voltage specification for your portable device. This can be found on the device power adapter label or device specification label which typically is found on the bottom of the unit.

And, they converted all the text in that pdf to curves.. To prevent people from copying and pasting their words?!?!

ARGH :P
posted by Chuckles at 4:50 PM on June 16, 2008