BK Precision 9110 60V/5A 100W PSU Review (With Pix!/Teardown) - Page 1
Forum section: electronics / general

author: MajorEE
author_rank: Contributor
timestamp: October 23, 2011, 01:14:52 am
content: Greetings,I'd like to introduce you guys to the BK Precision 9110 Power Supply, It's a 100W 0-60v, 0-5A, Linear/switching supply.Specifications:Output Rating: 0-60v, 0-5A, 100W MaxLoad Regulation: <0.01% +3mV/<0.01% +3mALine Regulation: <0.01% +3mV/<0.1% +2mASetting Accuracy: <0.05% +10mV/<0.2% +2mADisplay Accuracy: <0.05% +10mV/<0.1% +2mARipple: <2.0mVrms/<5mArmsFeatures:CompactDigitally Controlled Mixed Mode Linear/Switching PSU10mV/1mA resolution over full rangeOCP, OTP, OVPOutput On/OffSo I was debating this supply for quite some time (3 Months) before ordering it, purchasing this was far from my average company experience. I had talked with a gentleman from Fotronics Corporation (Test Equipment Depot) back in august and then contacted the company again here in October. The guy happened to remember me by name which was incredibly surprising. I happened to even score a bit of a student discount!I ordered this supply because I wanted something higher quality than your average "One Hung Low" PSU, which I definitely got. This supply is incredibly well built in nearly every aspect. The rotary encoder is very smooth, the buttons are easy to press and big enough for even people with large fingers. This supply will replace my Transformer/linear reg and various wall-wart supplies.The settings do require a quick glance at the manual but are pretty easy to understand afterward. The manual only comes in English and there is very little waste in packing material which I'm quite happy about. (Go Green WOO!!!)Unfortunately I do not have access to a digital scope to do some measurements and my school is really cheap and doesn't have a Lab. I will however put it on my analog scope when I get a chance and see what I can show you guys! I did however verify the display is incredibly accurate with my Fluke DMM, you can really trust the readings. One neat trick I'm sure many of you know is to set the constant current just above your needed current so it will not fry your chips in case of short circuit.What I dislike about this supply is that it doesn't have the ability to use shielded banana plugs which is all I currently have, it has a relatively loud fan (but not high pitch!), and in my opinion should have some different color indication to help differentiate between CC/CV and whether the supply is on/off at a glance.I would like to let others know this supply does not come with plugs of any kind like many other supplies do so until I can get to ordering some I will have to suffer with some wire and alligator clips.I am trying to work on a video review but I need to get my video editing software installed before I can upload it, I did get some video of the inside while I had it opened up though. Anything in particular you guys want to see done? Let me know and I'll try to get a video/picture for you.

author: Bored@Work
author_rank: Super Contributor
timestamp: October 23, 2011, 08:14:20 am
content: This might be a rebadged/customized-for-BK ITech Electronics IT6720http://itech.sh/en/productview.jsp?id=54&sortid=002Although yours has a different front panel.

author: bogdan546
author_rank: Contributor
timestamp: October 23, 2011, 03:45:38 pm
content: should not be up to 300w?

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: October 23, 2011, 03:58:40 pm
content: It has differerent voltage ranges with different max. current. E.g. for 60V, der current is limited to 1.6A, only for <20V you can get 5A.

author: Wartex
author_rank: Frequent Contributor
timestamp: October 23, 2011, 09:25:51 pm
content: Quote from: BoredAtWork on October 23, 2011, 08:14:20 amBingo. I spent half an hour looking for the original on ebay because I know I've seen it, but none came up because i used "0-60v" as a search term. Now if you try "60v 100w"http://www.ebay.ca/sch/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=60v+100w&_sacat=See-All-CategoriesApparently BK doesn't manufacture anything.

author: FenderBender
author_rank: Super Contributor
timestamp: October 27, 2011, 01:52:46 am
content: Most lab supplies aren't getting hammered with continuous use, but from a manufacturer like BK, no offense, I'd like to see something a little bit better than Lelon electrolytic caps in there. Not the worst of all choices, but some Japanese brand would be much more assuring.But appart from that, it looks decent.And yeah I don't know if BK even makes anything these days. I was going to buy the 2530b scope because it's the cheapest scope I could find from a reputable "US" "manufacturer", but maybe the quality won't be any different than a Rigol after all...

author: BravoV
author_rank: Super Contributor
timestamp: October 27, 2011, 06:16:58 am
content: Quote from: FenderBender on October 27, 2011, 01:52:46 amAgree, especially looking at the Teapo brand used under those power section, these particular brand are well known to bulge at it's top under moderate hot temperature within one year, and possibly dried up fast in hotter area.If I were you, I would inspect it after 6 months of use, especially those Teapo caps that are under the power transformer.Btw, thanks for those pics.

author: quench
author_rank: Newbie
timestamp: November 23, 2011, 04:04:15 am
content: MajorEE - do you have any additional thoughts on this power supply now that you've had it for a bit? I'm curious how well it is working out for you.

author: ipman
author_rank: Regular Contributor
timestamp: November 26, 2011, 01:06:13 pm
content: My advice is to replace all Lelon capacitors. Their quality is awfull. Teapo is just a little bit better, if you can replace them too.Choose replacement wisely from Panasonic/Matsushita, United Chemicon, Rubycon, Suncon (former Sanyo) and they will last for a long time.

author: avogra
author_rank: Newbie
timestamp: November 06, 2012, 12:17:27 am
content: Hi everybody,I recently bought this power supply, as the specs look quite nice and the comments here looked ok to me. Maybe my two cents are usefull to someone else, as this seems to be the only topic in a forum about this PSU.First, what convinced me to buy it:- small footprint- high voltage and current rating- mixed-mode meaning low dissipation and still low ripple- overvoltage and overcurrent protection - this could come in handy when you first power up a circuit. Set overcurrent protection a bit above what you expect the circuit to take. If something is wrong, it will just power off and your circuit might survive.- dedicated output enable button- digital control - nice, if you want to set a exact current limit. you don't have to find it with outputs shorted, just enter it!- save some standard setpoints as preset - not really needed, but i won't complain.looks cool so far. not the cheapest but seems like a good deal from a known company, so take it!when it arrived, i did some tests and the disaster started:Interface:- when you power it up, but don't enable the output, it doesn't show the set current and voltage but actual values. guess what ... both zero, very helpful -.- only when you turn the wheel to adjust values or press a button, the display is showing the set values, blinking for 3 seconds. after that, zero again. This is pointless and annoying!- when you then press the enable button, it's NOT showing the actual values, instead again 3 seconds of blinking setpoints. only after that, you see if you draw 10mA or 1000mA. come on! I want to see instantly, what is happening! when i set 50V instead of 5V by accident, it's too late to tell me now. stupid!- overcurrent / overvoltage protection: i tried setting an overcurrent protection for the purpose, i descibed above. it takes like pressing buttons 10 times to accomplish that -.- ok, i won't need it too often. BUT: this setting is also the top value for the usual current limit. I saw it coming - the PSU will go into current limit before the protection kicks in. yep, I was right, and it comes even worse, see Electrical.- generally, many other settings are a bit awkward to reach. thats not too severe, but i have seen better.Electrical:- a rise time of ~700ms from 0V to 10V at no load seems quite a lot (see screenshot). that's certainly better than overshooting. Still I'm a bit puzzled at that long a time. Not what I expect from a quality PSU.- but you don't have to search for the overshooting for long - you can't miss it when looking at constant current mode. and here, this unit proves, that it doesn't take half-measures :-P look at the screenshots!some tests might be unfair (10V/20mA, 30V/100mA), but when I set to e.g. 3V/20mA like for a LED, it produces still an overshoot of factor 6.5!! it takes about 80ms to find back to 20mA. at 1V/20mA it's still factor 3,5 and takes ~180ms to find home! the results for other settings don't look different. unfortunately, I have no capable resistors at home. At work, I also did some tests with higher currents. same thing at 1 or 2 Amps.Ummm, now I know the reason for the slow voltage rise time. If it had been faster, those figures would have been even worse ^^- then, the promoted overcurrent protection (dotted line) does exactly ... nothing! more than 100ms limit exceeded in case of 1V/20mA. Doesn't matter, it had lost its use to me already (see Interface) :-P- finally, there is one single good point: when the unit has decided to settle, current and voltage are quite accurate and ripple is indeed no issue. who cares about some oddities and spikes :-PDo i have to say anything about my final opinion on this? YES!!! :FAIL!!!!!!!!Sorry for the longish rant, I simply had to vent my anger. And maybe it's even useful to the next one to buy this ***. I'm off, browsing for a new PSUBye, Alex

author: tom66
author_rank: Super Contributor
timestamp: November 06, 2012, 12:30:09 am
content: It looks like they've attempted to solve past over-shooting problems with more capacitors. It is not the right way to do things.Also, in a hot, often abused linear supply, Teapo, Ltec and Lelon will not last. It's not expensive to use decent capacitors and you rarely need so many to make a good quality, reliable product.

author: pinkman
author_rank: Regular Contributor
timestamp: August 20, 2014, 03:09:18 pm
content: MajorEE,You need to do a more detailed review of this power supply. I just bought one of these. It is poorly designed and has serious instability issues. They appear to have tried to correct this with output capacitance, but as the above poster stated, this is not a way to fix such problems - It is a small bandaid which can be broken easily.I have a junk supply that I got for 99 bucks, no brand on it, and it outperforms this supply by far. I am seriously dissapointed in BK for this.I would recommend that you do a stability analysis on any power supply that you evaluate.

author: German_EE
author_rank: Super Contributor
timestamp: August 21, 2014, 04:49:17 pm
content: The rats nest of wiring does not impress me, it looks like they have not heard of wiring looms and tie wraps.

author: jlmoon
author_rank: Unknown
timestamp: August 28, 2014, 07:28:45 pm
content: Quote from: Wartex on October 23, 2011, 09:25:51 pmThis one looks very similar to a Kikusui product.

author: Zucca
author_rank: Unknown
timestamp: September 01, 2014, 08:20:06 am
content: https://www.eevblog.com/forum/testgear/mastech-dc-power-supply-hy3005dx-cheap-and-very-impressing!/Like night and day....