Author Topic: EEVblog #315 - Korad KA3005P Review/FAIL  (Read 164854 times)

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Offline george graves

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #125 on: July 23, 2012, 10:23:59 am »
I think I'm going to go ahead and buy one.  It seems you can get one in the US for $100 shipped - with a 2 year warranty.  Even if it lasts 2 years and 1 day, then blows up, that's still a heck of a deal, and should suit me just fine.  There is very few times I need more than 1 amp - so in my case, it should see very light use. 

I'm just so impressed with the accuracy of the displays, and the controls.  It seems like a +$300 PS for $100.

There were a few people stating "well, see, you can't make a decent programmable PS for $100! - Told ya!" - well, why not?  It's a transformer, a case, some LED's and a hand full of other parts.  I don't see why not.

I'd like to buy something that is a bit more "industry standard" - but in a pinch, this will do nicely.  And in two years, I'm sure I'll have added a lot more equipment to my lab.

My 2 cents.

Offline HackedFridgeMagnet

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #126 on: July 23, 2012, 02:25:45 pm »
I did a quick search on QA vs QC and this was the first site found. They even have a picture.
http://www.iso9001consultant.com.au/QA.html
Quote
Quality Control does not ensure quality, it only finds instances where quality is missing.  Obviously it's better than nothing, but it has its limitations.  The most important of these is that you only find out that things aren't OK at the end of the process.

Quality Assurance developed from the realisation that quality could be improved by looking 'further up the line'.  It is aimed at preventing nonconformities/defects.

QA still has QC at its core to control the quality of service/product, but it goes beyond mere testing or inspection to also consider related activities or processes (such as training, document control and audits) that may be resulting in defects further down the line.   
I dont know if it's right or wrong but it is not consistent with what you say.

Quote
If you are not knocking Trio Smartcal's QA, what on earth have you been whinging about?
The nub of what I have been trying to say is that a company having QA accreditation doesn't assure me personally of anything.
The psu failing only reinforced this view.
Whereas the brand name Trio Smartcal does give me reason to feel assured, because I have heard of them, have dealt with them and know of others that do the same.
 

Offline taemun

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #127 on: July 23, 2012, 05:14:59 pm »
"Considering that you can buy that Korad for $US 75 on AliExpress (plus postage), I wouldn't expect anything good to come from them. Sticking "Lab Grade" on a product doesn't make it so."

I have only seen the D and not the P(rogrammable) version at AliExpress...

Apologies, I didn't notice the D suffix as opposed with the P suffix. My point still stands though, that isn't $100 worth of isolated USB/RS232 board.
 

Offline amspire

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #128 on: July 23, 2012, 05:36:32 pm »
I did a quick search on QA vs QC and this was the first site found. They even have a picture.

What that graph is not explaining is that QA is about defining and managing the processes in a company, not the quality of products. As QC is a subset of the processes in a company, it is under the QA, but the QA processes are only concerned that your QC is running in a proper way. A manager in the company defines how QC should operate, and then QA ensures that these rules are followed.  QA is about defining comprehensive processes and rigorously following these processes, rather then making it up as you go along. So if a product fails, rather then a manager saying "What will I do now?", people look up the QA manual to see what steps have to be taken, and they follow the steps. QC is only shown as part of QA in the same way that every other process in the company will become part of QA.
Quote
Quote
Quality Control does not ensure quality, it only finds instances where quality is missing.  Obviously it's better than nothing, but it has its limitations.  The most important of these is that you only find out that things aren't OK at the end of the process.

Quality Assurance developed from the realisation that quality could be improved by looking 'further up the line'.  It is aimed at preventing nonconformities/defects.

QA still has QC at its core to control the quality of service/product, but it goes beyond mere testing or inspection to also consider related activities or processes (such as training, document control and audits) that may be resulting in defects further down the line.   
I dont know if it's right or wrong but it is not consistent with what you say.
It is consistant if you understand what I have been saying. QA means you are dealing with a company that will handle complaints in a standard manner. You are not at the mercy of the mood of the representative you are talking to. Dealing with company with good QA standards is a good thing, but not in the way that I think you want.

I think you want a quality product.

QA does not care less about the quality of a product unless the company has written rules defining a process to determine the quality of a product. Once there are rules, then ISO9001 QA requires that the rules are followed, and if they are not followed properly, a non-conformance report must be raised within the company. This non-conformance report must then be acted on in some way - it cannot be ignored. If the independent ISO9001 inspectors see there are non-conformance reports that have not been addressed, they can suspend the company's ISO9001 accreditation.
Quote

Quote
If you are not knocking Trio Smartcal's QA, what on earth have you been whinging about?
The nub of what I have been trying to say is that a company having QA accreditation doesn't assure me personally of anything.
The psu failing only reinforced this view.
Whereas the brand name Trio Smartcal does give me reason to feel assured, because I have heard of them, have dealt with them and know of others that do the same.
It does not assure you that a product the company is selling is high quality. If they are selling a low quality product, you get a low quailty product, and that is totally fine with a good QA system.

However, a good QA process is important when companies have to cooperate as it means that the QA processes of the 2 companies can be set up to work together efficiently. A big reason Trio Smartcal has ISO9001 is because many other potential clients, particularly governmental organisations, require they have ISO9001. These customers will not do business otherwise. That is why the ISO9001 compliance is advertised.

Richard.
« Last Edit: July 23, 2012, 06:20:49 pm by amspire »
 

Offline Galenbo

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #129 on: July 23, 2012, 07:00:46 pm »
...
It does not assure you that a product the company is selling is high quality. If they are selling a low quality product, you get a low quailty product, and that is totally fine with a good QA system.
...

And even, to produce absolute CRAP products, you need good machines and a good Quality control,
when not, you'll not be able to produce CRAP in high volumes
If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.
 

Offline HackedFridgeMagnet

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #130 on: July 23, 2012, 07:49:58 pm »
I don't wont to think about Crap in high volumes, it's dinner time.

You're probably right, Richard
But from personal experience, I see a red flag when people mention QA accreditation.
I'll leave there.
 

Offline MBY

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #131 on: July 25, 2012, 07:13:59 pm »
After rewatching the review it looks like more than just the power transistors failed; why would it switch to the 56V tap when the preset voltage was far lower? I'd think that a good control loop would notice the abnormally high output voltage and go to the lowest tap, then maybe even detect that the voltage is still too high and shut off completely at the relays.

56V also looks a bit high for a supply that's rated for only 30V.
Exactly my thought! It's a bit confusing when we have two "contemporary" threads about the PSU. In the thread http://www.eevblog.com/forum/product-reviews-photos-and-discussion/korad-ka3005d-$90usd-30v-5a-dc-programmable-ps/ I was also rising the concern that it not make real sense to assert that the transistors where the only thing failing.

As you said, the control loop should switch in the right taps for the right setpoint not matter the actual voltage. Maybe the control loop broke and put those transistors out of SOA. The transistor failing may be the effect, not the cause. It could be something as easy as a bad solder joint, especially if the schematics of the relays are dumb so non energized relays switch in the highest tap, not the lowest.

Btw, I agree with Scopeman1 - lets keep the QA and ISO stuff outside the thread. The electronics is more exciting. 
 

Offline itdontgo

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #132 on: July 25, 2012, 10:40:50 pm »
I know that beeper sound, it's using a beeper that requires the micro to generate the tone. (They're cheaper than beeper with internal tone generators)

When you try and generate the ~2kHz by setting/clearing the mcu output pin in software other interrupts will semi-randomly delay the set/clear commands and you get a sound that's dirty like that.

To avoid it they need to use the dedicated hardware timer output pin on the mcu so the tone generation happens independently.
(or a beeper that does the tone generation itself)

This can be useful when you play a melody through a piezo.  If you use a PWM the perfect square ware sounds louder and quieter around resonance.  The dirty software interupt driven output plays at a more constant volume!

Offline itdontgo

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #133 on: July 25, 2012, 10:42:30 pm »
Someone at Korad has been found out.

Offline LEECH666

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #134 on: July 27, 2012, 10:45:56 pm »
*Sigh* Why don't they offer that Agilten 36xx PSU + Free Multimeter deal in Euroland? I really would considder buying, but shipping cost + custom taxes would really take the fun out of such a deal.

:(
 

Offline MickM

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #135 on: August 06, 2012, 12:00:48 pm »
Hi;
  is there any update on this?
Was the problem found?

Mick M
 

Offline MBY

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #136 on: August 08, 2012, 05:45:20 pm »
I'm also looking for updates. Anybody has any news?
 

Offline TestBox

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #137 on: August 27, 2012, 11:54:47 pm »
According to Trio Smartcal there is a delay at Korad's factory. I got the impression Trio Smartcal was not very happy with Korad. Neither would I be if something dragged on this long. Apparently the parts to rectify the problem were supposed to be shipped weeks ago but Trio is still waiting.  Knowing the Chinese they'll be waiting a very long time.  Glad I didn't buy one from overseas.   :P
 

Online EEVblog

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #138 on: August 28, 2012, 12:00:30 am »
According to Trio Smartcal there is a delay at Korad's factory. I got the impression Trio Smartcal was not very happy with Korad. Neither would I be if something dragged on this long. Apparently the parts to rectify the problem were supposed to be shipped weeks ago but Trio is still waiting.  Knowing the Chinese they'll be waiting a very long time.  Glad I didn't buy one from overseas.   :P

Korad have said they were moving office location which has caused the delays.

Dave.
 

Offline GEuser

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #139 on: August 28, 2012, 03:14:37 pm »
Mr EEVblog , what is that bendy thing on the bench on the right in the video , a light?

cheers , Paul .
Soon
 

Offline T4P

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #140 on: August 28, 2012, 05:13:44 pm »
Mr EEVblog , what is that bendy thing on the bench on the right in the video , a light?

cheers , Paul .

His brand new mantis elite microscope
 

Uncle Vernon

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #141 on: August 28, 2012, 05:17:26 pm »
Mr EEVblog , what is that bendy thing on the bench on the right in the video , a light?

cheers , Paul .

His elbow?
 

Offline GEuser

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #142 on: August 28, 2012, 10:46:40 pm »
Thanks very much T4P , great gizmo and "i love the smell of mantis in the mornings"  ;D

@UV , LOL

cheers....
Soon
 

Offline ProBang

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #143 on: October 29, 2012, 05:17:26 am »
Hello

According to Trio Smartcal there is a delay at Korad's factory. I got the impression Trio Smartcal was not very happy with Korad. Neither would I be if something dragged on this long. Apparently the parts to rectify the problem were supposed to be shipped weeks ago but Trio is still waiting.  Knowing the Chinese they'll be waiting a very long time.  Glad I didn't buy one from overseas.   :P

Korad have said they were moving office location which has caused the delays.

Dave.


Yeah, that's two month ago. IMO enough time to establish business as usual.
Once more:

I'm also looking for updates.
Is there any update on this?
Was the problem found?
Anybody has any news?

Greetings,


Hartmut
If you think my english is bad...
- then should you read my french!
 

Online EEVblog

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #144 on: October 29, 2012, 08:40:50 am »
Yeah, that's two month ago. IMO enough time to establish business as usual.
Once more:
I'm also looking for updates.
Is there any update on this?
Was the problem found?
Anybody has any news?

Charles copies me on the email correspondence, which basically consists of him getting more miffed by the day they haven't responded, and Korad coming up with a new excuse each time. I think the latest excuse is that they haven't finished the Labview driver!

I think both of us have given up all hope of ever getting the problem resolved. And Trio are left holding a bunch of these lemons in stock.

Dave.
 

Uncle Vernon

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #145 on: October 29, 2012, 09:22:02 am »
And Trio are left holding a bunch of these lemons in stock.

Dave.
What Trio do have in stock, if your after a budget priced PSU, is the QJE PS-3005, it's no programmable, it's not the quietest electrically or audibly. Still at under $100, it remains a bargain and a good entry level alternative for those wishing for a basic 0-30V 5V supply.

http://www.triosmartcal.com.au/dc-bench-supplies/2631-qje-ps3005-bench-power-supply-150w-0-30v-0-5a.html

 

Offline ProBang

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #146 on: October 30, 2012, 10:15:32 am »

Hello

@ Dave

Very disappointing, how this manufacturer take care about his customers.  >:( :(

BTW:

I've seen the Korad PSU in the background during some videoblogs.
In the last blogs no more...
Find the PSU the way, following a ballistic curve, straight from the bench into the bin?

If not: Maybe you want to make some research to fix the thing?
(Of course: As far as it is possible for you.)
I think, it would be a great help for the owners of this unit.
Probably most of them are customers, who can't change to an agilent one.
Korad left them alone, as you can see...  :'(


@ Uncle Vernon

What a coincidence...
Possibly a bad man would say:" Two heads sharing together one mind - because it's more economic..."  ;D

I've bought exact this PSU some weeks ago. (The german re-badged version, you know.)

Look at this: http://www.electrobi.de/Energie/Netzgeraete-und-Netzteile/Labornetzgeraet-einstellbar/Labor-Netzgeraet-McPower-LBN-305-0-30V-0-5A-regelbar-LCD-Anzeige.html#review

It's far away from the league, where the Korad wants to play.
But it has one big advantage: It doesn't blow off my connected circuits.  :)

Greetings,


Hartmut
If you think my english is bad...
- then should you read my french!
 

Online EEVblog

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #147 on: October 30, 2012, 12:17:49 pm »
I've seen the Korad PSU in the background during some videoblogs.
In the last blogs no more...
Find the PSU the way, following a ballistic curve, straight from the bench into the bin?
If not: Maybe you want to make some research to fix the thing?

I sent it back to Trio (it was a loaner after all).
I don't want anything more to do with it.

Dave.
 

Offline grenert

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #148 on: November 06, 2012, 01:47:49 am »
Charles copies me on the email correspondence, which basically consists of him getting more miffed by the day they haven't responded, and Korad coming up with a new excuse each time. I think the latest excuse is that they haven't finished the Labview driver!

I think both of us have given up all hope of ever getting the problem resolved. And Trio are left holding a bunch of these lemons in stock.
Couldn't see that one coming  ::)
There's a reason why One Hung Low companies all get lumped together as such.
 

Offline KORAD TECHNOLOGY

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #149 on: November 10, 2012, 06:44:41 pm »
Hello, for KA3005P, Charles has tested and all is excellent. And he will work with Dave to post the good video review very soon.  :)
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