Author Topic: EEVblog #315 - Korad KA3005P Review/FAIL  (Read 251877 times)

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Offline T4P

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #225 on: January 26, 2013, 10:12:36 am »
Little close? Nah. If there are 3 taps it only needs to dissipate 50W, in any case any more than that results in requiring a MUCH larger heatsink anyway
 

Offline pomonabill221

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #226 on: January 26, 2013, 08:23:17 pm »
Little close? Nah. If there are 3 taps it only needs to dissipate 50W, in any case any more than that results in requiring a MUCH larger heatsink anyway

Yes you are right... after I posted this I thought about what I said and realized that this is one of the reasons they have the four different bus voltage selections, to keep dissipation down, use small heatsink, "cheaper" transistors, smaller ballast resistors, etc.

One thing I am going to test is when the relays switch (changing voltage setpoint), does the output bounce around?  (this is a question that I am going to try and resolve).

Another thing... when switching the output on, is the relay switching causing the overshoot on turn on (another question I am going to try and answer)?

This would indicate to me that the output should be enabled FIRST, then applied to the binding posts after a short delay (after the supply has settled), and I might just makeup a delay to do this so I don't cook something from the turn on overshoot.
 

Offline george graves

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #227 on: April 24, 2013, 12:15:55 am »
For USA folks.  SRA solder has these on sale for $95 shipped on ebay today.

http://www.ebay.com/itm/KORAD-PROGRAMMABLE-PRECISION-VARIABLE-30V-5A-DC-POWER-SUPPLY-DIGITAL-LAB-GRADE-/110888868115?pt=LH_DefaultDomain_0&hash=item19d17dd913

The ebay user id is randyruby - but it's SRA solder.

I couldn't resist - I order two.

Offline hgg

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #228 on: May 14, 2013, 08:27:01 am »
Hi,

I would like to buy a bench power supply and I think I will buy the programmable Korad.
http://www.ebay.com/itm/110888868115

Apart from the stability problems that they are supposed to be fixed, I've seen some cases
were the main power on/off switch has failed.  Do you know if they have fixed that as well?

Some questions for the owners of this power supply:
- Is it silent?  Is the fan always on, or only when needed?
- Does it make any hissing noises with a load or without one?
- Does it have any overshoot problems?

I am already over-budget by buying this power supply.  Do you think its a good option for
the money?  Are there any better ones for a similar price?  (not used ones)

Thank you!
 

Offline iloveelectronics

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #229 on: May 14, 2013, 08:44:00 am »
I would like to buy a bench power supply and I think I will buy the programmable Korad.

Try the Vantek 3305P instead. There was a thread on this PSU some time ago: https://www.eevblog.com/forum/reviews/vantek-dps-3305p-32v5a160w-programmable-dc-power-supply/

It doesn't overshoot, and it actually has 5 preset buttons for M1 to M5 :D, and they work as they are supposed to. I read before that the Korad's presets don't really work the way they should, you could change the settings even without overwriting them explicitly.
My email address: franky @ 99centHobbies . com
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Offline hgg

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #230 on: May 14, 2013, 09:17:21 am »
...but do you know where can I buy the Vantek from?
(I live in Greece).
 

Offline iloveelectronics

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #231 on: May 14, 2013, 10:03:28 am »
...but do you know where can I buy the Vantek from?
(I live in Greece).

Here's one on eBay: http://www.ebay.com/itm/Programmable-Variable-Adjustable-DC-Power-Supply-0-32V-0-5A-USB-AC-110-220V-/281101170639?pt=LH_DefaultDomain_0&hash=item4172ef77cf

But make sure you confirm with the seller you're getting the Vantek or Caltek branded ones. Apparently identical looking units with a different brand name do overshoot.

I have also sourced a couple of these for another forum member some time ago. The one I bought for my own use very recently seems to look different internally though, perhaps they have revised the design since that discussion thread above in 2011.
My email address: franky @ 99centHobbies . com
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Offline hgg

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #232 on: May 14, 2013, 11:09:33 am »
Hi, thanks I will check that out, although it ships from China...

So do you mean that the Konrad is a re-branded Vantek ???
 

Offline hgg

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #233 on: May 14, 2013, 11:36:26 am »
I also saw in the photos that the Vantek has a toroidal transformer.
I assume that this is better, correct?
 

Offline iloveelectronics

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #234 on: May 14, 2013, 01:22:28 pm »
Hi, thanks I will check that out, although it ships from China...

So do you mean that the Konrad is a re-branded Vantek ???

As far as I know, no, they are manufactured by different companies.
My email address: franky @ 99centHobbies . com
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Offline iloveelectronics

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #235 on: May 14, 2013, 01:41:20 pm »
I also saw in the photos that the Vantek has a toroidal transformer.
I assume that this is better, correct?

I think there are pros and cons, but I'll leave this to the more qualified and knowledgeable members to answer.
My email address: franky @ 99centHobbies . com
My eBay store: http://stores.ebay.com/99centhobbies
 

Offline hgg

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #236 on: May 14, 2013, 07:08:24 pm »
In the case of the Korad, I can only find the one with the 220V transformer.
I've heard that there is a version with a 240V transformer as well. 
Here in Greece we have 230V.  Do you think I will have any problems?

Thanks.
 

Offline madires

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #237 on: May 16, 2013, 08:16:54 pm »
In the case of the Korad, I can only find the one with the 220V transformer.
I've heard that there is a version with a 240V transformer as well. 
Here in Greece we have 230V.  Do you think I will have any problems?

Should work fine since a proper PSU is designed to run with 10% under/overvoltage.
 

Offline hgg

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #238 on: May 16, 2013, 09:53:14 pm »
Just bought it.... Thanks.   :)
 

Offline nelsonro

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #239 on: May 24, 2013, 02:24:50 pm »
Found a different kind of fail with a re-branded tenma psu... if you look at the model it says 2x 3A outputs + 1 fixed 5v rail but this unit its a 2x 5A output with no extra 5v rail lets just hope they didin't just flash the wrong firmware in it  |O to make it go to 5a.


didn't notice at the time but this one doesn't have pc connection.
Also tldr all so don't know if anyone found how to go to m5... actually found it by accident, just press m4 and rotate the adjust knob clockwise
 

Offline leniwiec

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #240 on: January 06, 2014, 10:52:49 pm »
I also have two of them, and now warranty for them had ended, so I decide to make it less noisy ;-) If somebody interest, take a look on my ultra simple hack here http://www.leniwiec.org/en/2014/01/06/korad-ka3005d-silent-fan-hack/

Cheers!
 

Offline pomonabill221

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #241 on: January 07, 2014, 01:48:13 am »
Took a look at your mod (not really a hack though) and left you a comment.  Nice work and I just might do the same.
My supply may be a later one though as on the heatsink, every other finger is bent over so the air must pass by the fingers.
I have had the thermal trip the supply due to overheat, so a larger heatsink seems to be the way to go!
 

Offline leniwiec

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #242 on: January 07, 2014, 03:52:26 am »
Thx pomonabill221. Yes, it is nothing big, I just wrote about it because want to share my opinion about this units ;)
 

Offline pomonabill221

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #243 on: January 07, 2014, 03:57:27 am »
Thanks!
Thx pomonabill221. Yes, it is nothing big, I just wrote about it because want to share my opinion about this units ;)
Thanks!  Yes it is a cheapy and has "limited" performance, but it isn't an HP/Agilent/Lambda and it doesn't have the price tag either!  Just remember that when using it (really a comment to everyone).
 

Offline GiskardReventlov

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #244 on: January 31, 2014, 10:55:50 pm »
A general question about the testing process.  I've seen this in other videos here too. Dave had his BK connected to the Korad. No doubt I'm missing some basic knowledge here. Why did he have power going in to a power supply? I know he touched on this but I didn't get it. It seems this was important to revealing the failure, right?
 

Offline jancumps

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #245 on: January 31, 2014, 11:04:23 pm »
A general question about the testing process.  I've seen this in other videos here too. Dave had his BK connected to the Korad. No doubt I'm missing some basic knowledge here. Why did he have power going in to a power supply? I know he touched on this but I didn't get it. It seems this was important to revealing the failure, right?
That device can sink power. He uses it as a configurable load.
 

Offline GiskardReventlov

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #246 on: January 31, 2014, 11:12:39 pm »
That device can sink power. He uses it as a configurable load.

"That device" == "He uses it" == BK?

If my understanding's correct above, you're saying that the BK can handle power in either direction. Is that right. It can act as a multimeter. I think he said that in the video but I wasn't clear on that.  I think he did same in the Rigol DP832 video (which also had serious issues).

If my understanding's not correct of what you meant, then what did you mean?
 

Offline jancumps

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #247 on: January 31, 2014, 11:17:13 pm »
That device can sink power. He uses it as a configurable load.

"That device" == "He uses it" == BK?

If my understanding's correct above, you're saying that the BK can handle power in either direction. Is that right. It can act as a multimeter. I think he said that in the video but I wasn't clear on that.  I think he did same in the Rigol DP832 video (which also had serious issues).

If my understanding's not correct of what you meant, then what did you mean?

It is a programmable load. So you can configure the amount of load it will apply to the source.
" A configurable consumer of energy "
 

Offline GiskardReventlov

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #248 on: January 31, 2014, 11:29:54 pm »
It is a programmable load. So you can configure the amount of load it will apply to the source.
" A configurable consumer of energy "

That makes a lot of sense, thanks!

I would never spend money on this Korad.  Dave is a good man, because this thing is a disaster and I believe he was being quite generous to Charles and Korad. Maybe Korad shoud be looking for new hires. There are literally millions and millions of college graduates in China looking for work.

Now I will go look to see if he reviewed any legacy PS that can be found for low $, these new low $ supplies are too much crap. Buying one at any price encourages them to keep making them. Dave's become their personal Quality Control engineer.
 

Offline jancumps

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #249 on: January 31, 2014, 11:56:13 pm »
It depends on what you need. My PS is crappier than that Konrad and it serves me well.
As long as you know the limits, and the limits don't stop you from doing your work...
 


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