I picked up a Drobo at a yard sale that was missing the power supply. I happen to have a power supply that’s the correct voltage however the plug size on the power supply is 5.5mm x 2.1mm which isn’t fitting in the Drobo Gen 3. I can’t for the life of me find the correct plug size information on the site or on the internet. Does anyone know what it is? I’d rather pick up a plug adapter than buy another power supply.
Thanks!
hi i had a look on the specs page and found this info:
External Power Supply:
AC Input – 100-240VAC~2A, 50-60Hz
DC Output – 12V, 4.16A, 50W max
(though could not find anything about the mm size of the plug or polarity info)
there may be some additional information i missed from the online quick/deep guides though:
http://dashboardhelp.drobo.com/guide/230/en/index.htm
http://myproducts.drobo.com/AA-00905
and possibly gently inspecting the sides or underside of the drobo might reveal some plug information and polarity details (but best not to do that unless the drobo is powered off, and drives removed, and then when finished inspecting, to put the drives back where they were, before powering on)
(its just a slight caveat as i know you do not have power but if i get into the better habbit of trying to mention it that way, its probably for the best), especially if others visit or revisit this page in future when a working drobo needs a new psu 
I appreciate the post Paul. I’ve looked through lots of docs on Drobos and the only mention of the plug size was from a post on the drobospace forum where someone assumed the original drobo’s plug size was 5.5x2.5, center-positive http://www.drobospace.com/forums/showthread.php?tid=138017
From the looks of it I think 2.5mm might be the size but not 100% sure. The only thing I can think of is to use a Caliper on the Drobo to figure out what the actual size is. I’m also not sure what the polarity is. I was thinking about taking a chance and buying this 28/pc adapter set and hope there’s a size in there that works with the Drobo and the polarity is right http://www.amazon.com/Universal-Power-5-5x2-1mm-Adapter-Notebook/dp/B00XPB917Y
hi youre welcome,
getting a multiset seems handy (and i actually had one for helping to charge several different relatives mobiles back in the day when there wasnt a simple standard socket for plugging in adapters, heasets or power on a mobile phone) - oh wait - no change there then 
i think the closest thing i have seen is those figure of 8 power plugs (usually used in shavers or portable radios) which seem to work which ever way they are plugged in) but one thing to note is that the thread you mentioned was talking about a drobo mino (and while its possible the drobos in general might be designed in a similar way, i dont know for sure if a gen3 would also be that way), and as far as i know, having the right polarity is also important.
i guess what im saying is that its probably best to wait for someone else who knows for sure, rather then just buying and trying, in case you end up (pardon the pun) frying.
That’s for the mini. I am pretty sure the 3rd gen is 6.3mm x 3mm.
I ordered this size plug from Ebay to try it for about $4. I am going to build an adapter for it for my Series 2 adapter, which actually has a higher rating at 90W and is much easier to find.
Why? I bought a used Series 3 with no power supply for $75 and I want to see if it works before I do too much more.
I may also build some of these adapters to sell if the market is there.
I realized that after I tried plugging in another old laptop power supply which has a 5.5mm x 2.5mm and noticed it would not fit. The inner diameter is a tad larger than 2.5mm so your 3.0mm number might be right. I plan to use a caliper tomorrow to try and get the correct size.
How’d you come up with 6.3mm x 3.0mm? Do you happen to know the polarity?
I found this on ebay http://www.ebay.com/itm/2-Pcs-DC-Power-Plug-Jack-Change-Adapter-3-0x6-3mm-Male-to-2-1x5-5mm-Female-/131665968569?hash=item1ea7e73db9:g:sdAAAOSwp5JWXpFx
So measuring the size with a caliper was a fail due to how hard it is to get the tool into the plug hole with the stupid beveled plastic around it. I attempted to take the drobo apart but could not figure out how to take the back panel off so I ended up giving up. I’m gonna try bringing it to a few local computer shops this week to see if they can figure out the size. Still not sure what the polarity is.
hi, did you find anything on the underside or back of the drobo?
So looks like beachfitrob was right. I went into Radio Shack and had them try a bunch of plugs. 6.3mm x 3.0mm seems to be a winner. I’m gonna try ordering that connector off ebay and see if it all works.
ok please let us know how it goes
It appears to have worked! I have my drobo up and running with 4 HDDs in it. It’s been on for a few hours without any problems. 6.3mm x 3.0mm is definitely the correct size for the Drobo 3. In the process of running update’s on it now. Thanks beachfitrob for giving me the correct size.
cool nice one