BTW, this is the original fan http://portal.sunon.com.tw/pls/portal/sunonap.sunon_html_d_pkg.open_file?input_file_name=7264646F632F3230313430312F3137363539382F28443132303230383130472D3030292D322E706466
From the data sheet, it pushes 75 CFM (127,43 m³/h in normal units), the new one is rated for 100,6 m³/h, which equals to 59,21 CFM.
This means -20% airflow, but it doesn’t seem to be a problem at all.
If you look at noise, the old one was rated at 34 dB(A), the new one 18,1 dB(A).
Wow, good job. My solution would gave probably involved a hammer.
I purchased 4 or 5 Drobos for my company including a couple of the 8 disk models. Only had to contact them a couple of times and was pleased with their support. But that was years ago.
They were recently sold:
“A startup storage company, StorCentric, came out of stealth Tuesday with the news that it has acquired two long-established storage vendors, Drobo and Nexsan.
Sunnyvale, Calif.-based StorCentric, which describes itself as a “newly formed customer-centric storage solutions company,” appears to be using the acquisitions to introduce itself to the storage industry.”
This has sadly been the way of the world for a long time. I am already on my third or fourth car where I can’t ever replace a light bulb myself…
Serviceability is no longer a property anyone designs for. Either buy new and toss out the old, or use authorized service shops to fix simple stuff we all used to do ourselves.
Well done on reviving your Drobo, it may have many years left.
Thanks! I’m probably going to need to do this in a year or so to my 4 bay which is around 3 years old. It’s been going like a champion since day one.
I like the Drobo. Just stick some HDDs into it and it works. If a HDD fails, red light, just replace it. I also have a 5N and it does what I need: share storage on the network. I don’t need all the bells and whistles on my NAS, I run services on a Mac mini. I just wish for better service and more speed, especially on the DAS.
I like the way the Drobo lets you use hard drives of different space capacities and being able to pop out a failed drive, insert a new one and be back in business. However there is ONE problem with Drobo and that is having ONLY one Drobo. If the Drobo hardware fails all you are left with is a nice group of hard drives that you can’t access until you acquire a new Drobo unit. I removed my Drobo for that reason. I couldn’t afford to have a spare Drobo as a hot spare or pay Drobo for a maintenance contract. I also had a fan noise problem with my Drobo about four months after I purchased it and Drobo did sent me a new unit since mine was still under warranty.
Data should be backed up. So, if the Drobo (or whatever device) fails, you still have…your backup .
Any reason the new fan would start up immediately when I plugged in the power adapter, and turn off when I turn on the Drobo? I have no idea what could have gone wrong, but even the old one does that now with or without drives… I’m going crazy 
I’m having the same exact issue today. Replaced the fan with the exact same Sunon model just now and when I plug in the Drobo the fan spins for a few seconds them stops when Drobo boots up. Then it never comes back on and Drobo overheats and shuts down. Did your ever solve your issue?
April 2020 update. I had the same problem and consulted an engineer in my family. Was able to order the exact fan, ADDA Corp, Model AD1212HB-A71GL from newark.com. See https://www.newark.com/adda/ad1212hb-a71gl/axial-fan-120mm-12vdc-230ma/dp/58P0851. Had the fan the next day and no problems installing. Only had to strip and fuse the two fan wires, but no extra wires to deal with. Your instructions to get into the box and to the fan were very helpful. Sure beats buying a whole new unit - which I understand are hard to get right now. Seems to be running great, but will watch for overheating over the next few days.
The ADDA fan (exact model) doesn’t work for my 5D
The fan only moved a little bit when I plug in power adapter and a little bit when I switch on Drobo, any clue?
Thanks for this write-up. One question though. you mentioned pressing from the inside to remove the reinvest. I did this, but I’m not seeing how to replace them. (I think I broke one of them in an attempt to put it back in place.). Are they single use only? If so, do replacements typically come with a replacement fan, or where would I order more?
Also, on Amazon, I see 12V 2-pin fans… would they not be the proper replacement (shout requiring the rewiring?
Did you re-wire the fan?
Side story.
My DAS 4-bay Drobos were sounding louder than usual, so I decided it was time to unplug and blow any dirt off the fans (as I have before). When I reconnected, I guess 1 drive wasn’t snapped in all the way, so it immediately went into protection mode. When the that was completed (and the drive back in) it said one of the drives went bad. I was able to reformat the drive, and it seemed ok. I put it into the older Drobo and it freaked out again (and did data protection for 80 hours, even though I put the original drive back). I think this happened to me previously, where a drive won’t work in Drobo, but works fine formatted. Can’t wait to move to a different system.
I recently did a similar fan replacement on my drobo 5D. I did however not go through the hassle of resoldering fan connectors. I got myself an external fan controller and just plugged the new fan into that. Now I can adjust the fan speed with ambient temperature and load if needed.
I had intermittent problems with my drobo for a while and the fan replacement was part of my attempts to mitigate those problems. Recently one of the drives died completely and that drive seems to have been the source of most of my problems. I contemplated replacing the drobo but I get 180 Mb/s read and write speeds and thats pretty ok for such an old device. I am going to replace a few more drives and run the drobo for a few more years. The money I save will go in to the Apple silicone Mac pro jar. It is probably going to need all the spare change I can give it.
In reply to my question re: 2-pin fans… I ordered a 2-pin fan, and then discovered that the Drobo, while only using 2 of the pins, uses a 3-pin connector… so I’m going to have to splice them anyway.
Rather curious as to whether a “real” 3-pin fan might perform better (perhaps Drobo save a buck or so by putting in a two pin fan)
3 wires: PWM control. Not implemented in the Drobo. PWM is used to control fan speed.
Thanks… somewhat suspected that. I would assume, that, if unimplemented, I could just plug in the three pin connector and the third wire would be “dead”. No need to clip it or do any modification. Is that a valid assumption? (Maybe I just need to go read up on all the two three and 4 pin fans and how they all work. Seems alike a lot of pain just to replace a noisy fan though)
WRONG!
As I wrote in my original post:
Now, your new fan: you need a 120mm fan with a 3 pin connector. Not 4, those have PWM control, THREE! I got this one: https://amzn.to/2CVp460 303 (I know, German, but you get the idea). Look for “silent” fans.
Problem: different wiring. Also see my original post.
As for “pain”: depends on what hurts you more, the noise or a little tinkering. Mine was making terrible noises, so probably about to fail. Was an easy fix for me, I am used to soldering. If you are not, might even be doable without it (strip, twist wires, ISOLATE!!!).
So what if the issue is with the case rattling - If I put put my hand on the metal case on the top the noise stops - this doesn’t seem to be a “fan” problem to me. Also has anyone else had an issue putting the front rubber “O-ring” back on once the case is removed?