BK Precision 8600 Electronic Load teardown photos/review

[dadler]

Hi all-

I ordered a BK Precision 8600 Electronic Load last week, and received it today.

The 8600 line is BK's newer series, and the 8600 model in particular is 120V/30A/150W.

This design is new, and internally is not similar to the others such as the Itech/Maynuo. It has onboard USB, RS232, and GPIB without need for any adapters.

The device works well, but I am not happy with the build quality. This may be normal for BK Precision--I have never before owned a BK precision product.

In particular:

- The tilting bail is flimsy
- Not a fan of lelon caps
- Internal PCB (at least the top IO board) is made from that thin stringy FR4 that you typically find in very cheap chinese products
- Rotary encoder knob spins off-center and is not flush with the front bezel during operation
- The piezo buzzer, instead of buzzing makes a sort of battery-dying-squelch sound that drives me batty
- Lots of flux on the board (not really a big deal, just a pet peeve)

The rest seems fine for the most part, but the fit-and-finish is poor. All-in-all, it does not feel like a $900 product. Any random Rigol product feels 10x better than this thing. Puts me off from ever buying another BK Precision product. I'm probably being picky, but I like my equipment to "feel" good in use, and this fails that test.

Photos:

[mcinque]

Thanks for sharing!
Why you choose BK and not Maynuo? Because of the USB/RS232/GPIB?

[PA0PBZ]

Did you already remove anything before taking the second picture? Because if I see a HP/Agilent with the screws showing like that I'm sure that there is some cover missing...



Ah, never mind

[TiN]

U401 likely to be ALTERA MAX CPLD series

[tszaboo]

NE5532 driving the FETs. Now, that is interesting. Thanks for sharing.

[Kjelt]

They did fix the operation of the mains switch with a long plastick extender instead of putting mains wiring across the entire side as in the previous product so they do look to the eevblog 

[dadler]

Did you already remove anything before taking the second picture? Because if I see a HP/Agilent with the screws showing like that I'm sure that there is some cover missing...



Ah, never mind

I think the holes are for the rackmount kit. There are pictures of it in the piss-poor manual that doesn't sit flat, since it seems to be hand printed and stapled? 

[dadler]

Other than the Lelon caps, I do like the main board. It seems to be made of thicker/higher quality FR4. And it does work well. I have not yet tested the performance of the IO, which I will do soon. No discs were included with software (nor is the software mentioned in the 'manual'). This would normally be a problem but I do not actually own a dvd/cd drive anymore  .

I am just a bit disappointed because Dave's 8500 review left me feeling that the build quality would be top notch. The functionally important thinge *are* top notch, but what would it have cost, $10? To address most of my build quality concerns? How can Rigol pull off such high build quality on cheaper products?

But the device, an electronic load in general, is a "great piece of kit" to have. I played around with it quite a bit last night and am already finding new uses for it. Once you have one of these, you realize how easy it is to exercise portions of circuits or sanity check your assumptions in a real circuit.

My main complaint probably seems the most petty: the damn rotary encoder knob absolutely sucks!!

[Kjelt]

My main complaint probably seems the most petty: the damn rotary encoder knob absolutely sucks!!

I myself have an Onyuo Maynuo and must say I have not much use for the rotary knob anyway. It is slow and you can just push the right setting numbers you want in straight away. No need for the knob.

[jlmoon]

U401 likely to be ALTERA MAX CPLD series

I just love it when they grind off the chip identification.   

[retemitlum]

My main complaint probably seems the most petty: the damn rotary encoder knob absolutely sucks!!

The rotary encoder knob on my Maynuo also sucked.
The problem was not with the knob itself, but the decoding of the knob was obviously not implemented properly.
I fixed it by adding a small microcontroller after the rotary encoder.
With proper decoding (state machine) the knob is much better.

[Kjelt]

The rotary encoder knob on my Maynuo also sucked.
The problem was not with the knob itself, but the decoding of the knob was obviously not implemented properly.
I fixed it by adding a small microcontroller after the rotary encoder.
With proper decoding (state machine) the knob is much better.

Please open a topic with this upgrade, love it! 

[dadler]

Thanks for sharing!
Why you choose BK and not Maynuo? Because of the USB/RS232/GPIB?

I almost went Maynuo (like, had it in my cart on eBay, sitting at the final confirmation screen).

Reasons I went BK over Maynuo:

- 3 year warranty from US company
- better software
- onboard USB and RS232 (I do not use GPIB)
- seemed to be a new design (wasn't sure 100% other than the IO)
- With shipping and import duty, the BK was only about $250 more (counting the tequipment EEVBlog discount I received on the BK)
- I like the round buttons on the front 

I don't regret getting the BK, but I do now classify them differently. I thought they were a cut above the other Chinese manufacturers (similar to Rigol), but the build quality on this unit is very much like the cheaper Maynuo. I still think the Maynuo and Itech are great devices and most people should get one of those instead, unless you need the bonuses you get with the new BK that I listed above.

[mcinque]

- better software

Never seen that. Do you have some screenshots to share? I'm very curious.

- onboard USB and RS232 (I do not use GPIB)

I guessed it. 

- seemed to be a new design (wasn't sure 100% other than the IO)

This is not always a good thing: any new design can have minor or major issues 

- I like the round buttons on the front 

[dadler]

- better software

Never seen that. Do you have some screenshots to share? I'm very curious.

- onboard USB and RS232 (I do not use GPIB)

I guessed it. 

- seemed to be a new design (wasn't sure 100% other than the IO)

This is not always a good thing: any new design can have minor or major issues 

- I like the round buttons on the front 

I was hoping that the internal design would be better, since BK Precision indicated that the 8600 was a "redesign" post-split with the original engineer who started Maynuo. It does seem that the board design is better, there is a hard power switch in the back with plastic button bar to the front panel. I like the new layout. But yes, it was a gamble. I don't like paying import duty, would rather it go towards "value" (real or perceived). Not sure if that worked out in the end, since the tactile build quality is poor. But it will probably do the job and I intend to keep it.

I'll post some screenshots of the software.

[dadler]

Ok, well I must have been confused thinking the 8600 software was better. It's not. It actually sucks. Maybe I was thinking the Maynuo software was the 8600 software?

Beyond the spectacularly horrible interface and non-standard menuing/button setup, the software hard locks if you turn off the device before disconnecting. You'll have to kill the process from task manager. I love how the window always has scrollbars, even when the window size does not justify it. I've seen this happen before in poorly written software-their code doesn't account for the width/height of the scrollbar itself vs the window size, so the window has perpetual unnecessary scrollbars.

The software does work, sort-of. You can really confuse it if you connect with the output already on, or change the output in local mode. It will think the output is inverted from its actual state in the software, and the only real way to get it back in sync is to disconnect/reconnect with the output off.

The transient feature works well, but I think the old software had that.













My advice to anyone wanting a DC Electronic Load is to probably get the cheapest one you can, because the quality will probably not be any worse than this expensive one.

[HighVoltage]

I have both, the BK 8500 and the Maynuo, and I find myself using the Maynuo much more often, because it just feels better and the software is a great deal better.

The new BK8600 I saw first at the last electronica in Munich 2014 and though ... wow, what a good design.
After your tear down, I see no reason to upgrade from the 8500 to the 8600, especially since the Maynuo has also 4 values on the screen.

Thanks for a great tear down and your impression.

[mcinque]

Thanks for sharing the screens!!!

[JohnnyBerg]

The software looks kind of "simple" ?
Is it possible to combine other instruments with it, or is it BK 8600 only?

[mcinque]

The cheapest is the Array, but it has a crappy software (worst than the BK); IMO the best choice is the Maynuo: it's not cheap but for its price it has good software, a good and trusted design and options and it's phyton scriptable (of course you need the usb adapter).

[dadler]

The software looks kind of "simple" ?
Is it possible to combine other instruments with it, or is it BK 8600 only?

Hmm, I'm not really sure what you are asking. You can program the thing via USBTMC/RS232/GPIB with standard SCPI commands. You have full control over the device. Programming docs: https://bkpmedia.s3.amazonaws.com/downloads/programming_manuals/en-us/8600_Series_programming_manual.pdf

I am considering writing my own UI if I continue to be this annoyed with the software (maybe Java or python, something that works on Mac as well. I'm pretty lazy so I will probably never do this. At most I expect I would script it via python.). The device has tons of features that are not accessible from the provided simple software. Some functions appear to only be available over SCPI.

I took a chance on this device because nobody else had one (despite one tiny glowing review on tequipment.net), plus Dave's extremely positive review of the 8500. In Dave's video, the 8500 build quality seems similar visually to my 8600. But once you get your hands on the thing, it feels like a cheap piece of junk. I've never held an 8500, so I can't speak to its build quality. Who would want a rotary encoder that acts like this!?!

Rotary encoder video: https://www.dropbox.com/sc/o8qu597hww114t2/AAC3LzcgC1e0s3Qdi2MLoNZPa

Another fun annoyance: You can't just plug the 8600 into your computer's USB port if the device is already running. It will only be detected if the 8600 is connected before you power it up. Took me a little while to figure that out, since it's not in the docs.

But the components seem good and the board appears well laid out to me. My rudimentary testing shows it meets its specs. I even like this giant binding posts on the front (though all the models have these). The aspects I am disappointed with are exactly those aspects that are supposed to make this device "better" than the cheaper Maynuo/Itech clones. At least I have a 3 year warranty?

All things considered, if I could do it over again, I would get the Maynuo or Itech. Slightly prefer the Maynuo because the software looks better, but don't trust me on that one.

[mcinque]

cheap piece of junk. I've never held an 8500, so I can't speak to its build quality. Who would want a rotary encoder that acts like this!?!

You can't just plug the 8600 into your computer's USB port if the device is already running. It will only be detected if the 8600 is connected before you power it up.

are you kidding?

This two things confirms that - for me - a new design it's not always a good thing and that BK it's only extremely overpriced stuff.

[HighVoltage]

Rotary encoder video: https://www.dropbox.com/sc/o8qu597hww114t2/AAC3LzcgC1e0s3Qdi2MLoNZPa

It seems like you can use the arrow keys to select the digit that you want to change with the arrow key.
Right?

[dadler]

Rotary encoder video: https://www.dropbox.com/sc/o8qu597hww114t2/AAC3LzcgC1e0s3Qdi2MLoNZPa

It seems like you can use the arrow keys to select the digit that you want to change with the arrow key.
Right?

Absolutely, that is what I do, I don't use the rotary encoder knob because it feels like it is going to snap off 

[HighVoltage]

Yesterday I was at the Nuernberg "Sensor and Test" trade show and visited the stand of the ITECH distributor for Germany.
They had the new ITECH DC Load there and it looked exactly like your BKP 8600 load.

The German distributor then claimed, that ITECH is producing the DC Load for BK Precision, but the ITECH version is suppose to be the better one.
Still interesting, that they all look the same!