EEVblog #315 - Korad KA3005P Review/FAIL

[David_AVD]

The plot thickens....   

[PA0PBZ]

https://twitter.com/eevblog/status/267132540182228992

[mikeselectricstuff]

Sticking "Lab Grade" on a product doesn't make it so."

Generally when you see things like "High Grade", "Professional" etc. actually written on a piece of kit it means the exact opposite.

[Bored@Work]

... Dave to post the good video review very soon. 

Can't wait to see THE GOOD VIDEO. However, I have the feeling you will be a bit disappointed.

[KORAD TECHNOLOGY]

... Dave to post the good video review very soon. 

Can't wait to see THE GOOD VIDEO. However, I have the feeling you will be a bit disappointed.

Thanks for your reply. I sincerely hope I won't 

[tom66]

Oh, I think you will. Mwhahahahahahahahaha...



I'll go back to my cave.

[Uncle Vernon]

... Dave to post the good video review very soon. 

Can't wait to see THE GOOD VIDEO. However, I have the feeling you will be a bit disappointed.

Thanks for your reply. I sincerely hope I won't 

It will depend entirely upon the performance of your product. Dave will give it a fair call, if the problem is gone and the fix looks permanent you may get something like the review you wish for.
 Ignore the talking heads in the cheap seats any review will be a fair call of the product as presented.

[Bored@Work]

It will depend entirely upon the performance of your product. Dave will give it a fair call, if the problem is gone and the fix looks permanent you may get something like the review you wish for.
 Ignore the talking heads in the cheap seats any review will be a fair call of the product as presented.

Well, I have the feeling that Dave is not sufficiently motivated to do THE GOOD VIDEO. Asking him to remove the old video (or else?) probably didn't help to motivate him to do THE GOOD VIDEO.

[grenert]

Generally when you see things like "High Grade", "Professional" etc. actually written on a piece of kit it means the exact opposite.

"Quality Product"

[tom66]

Clearly the original power supply transistors were completely insufficient for the task and blew up within a few minutes of use.

However, I fear that while Korad's modifications may pass the initial "Dave test" (i.e. the power supply works and performs well), they would be no good for long term reliability.

You cannot expect to make a decent linear power supply (30V, 5A) with a small heatsink and fan. Insufficient transistors will just make it fail quicker.

The only real world test I can think of is leaving it connected to a load at its maximum power dissipation (before a relay clicks in, and at the highst current possible), for several days, and see if it fails. That might give an idea of long-term reliability.

[T4P]

1V @ 5A ... That's torture

[tom66]

Not necessarily, it has a relay clicking in at around 8V, so the worst case would be the greatest voltage drop across the power transistors at full load. Which may occur around 1V, or 9V, or 20V, depending on how it is designed.

[T4P]

how about 0.1V 
39.5W is probably pushing the boundaries of what can be done with a aluminium sheet with holes punched in it to resemble a "heatsink" and slightly augmented with a fan that probably only achieves 20+ CFM and some pretty piss poor static pressure numbers.
I'm joking though but it can be true  It seems like this PSU really needs a LGA 775-ish heatsink (The OEM ones) as well as beefier transistors, not wimpy 2N3055s (Is it a 2N3055?) that only costs less than a dollar
Can't korad even fork out a few extra ten cents for a beefier transistor? 

[tom66]

This is what it takes to last 30 years. 35V, 3A supply using three Toshiba power transistors plus SCRs to automatically switch in transformer taps (three of them.) Plus an absolutely massive power transformer that's not going to saturate under load.

It cost me £30 from a local test equipment dealer, used of course - I'd hate to know what it cost new... It was made in Japan.

[Uncle Vernon]

Well, I have the feeling

The feeling eh? Sure it's not a vibe? Feelings are the domain of soothsayers, charlatans, faith healers and other assorted crackpots.

Dave is not sufficiently motivated to do THE GOOD VIDEO

Given the interest shown in this particular supply, a follow up video would depend mainly on the availability of time and relevant and interesting content.

Asking him to remove the old video (or else?)

Or else? There you go having your feelings again. Dave has stated his position on such requests many times,  something that has nothing to do with your old country feelings or xenophobia

probably didn't help to motivate him to do THE GOOD VIDEO.

I am sure Dave will be overjoyed to think there are nutjobs out there that believe he'd put a desire for retribution before a need to call it as he sees it now. It may not be common practice amongst your secret handshake set but unless you've missed it completely, much of Dave's reputation is based upon his giving no bullshit calls based upon actual results.

I'll be interested to see what Korad has done to rectify problems and whether it constitutes a kludge to get it past testing or modification sufficient to give the thing adequate reliability and longevity.

Given that Dave will get an actual device and you're working from racial bias, tea leaves and other non specific jiggery pokery don't be offended if those of us with a clue wait for Dave's replies while ignoring your rants. Have a nice day!

[Ed.Kloonk]

 

[EEVblog]

My enthusiasm for a new video is almost zip.
But if people really want a follow-up, I might put it on the list.
Charles has a video of him using the new model for welding or something, as a hack test of it's gruntiness, he will drop it off in a few days and I'll probably put it on my Altzone channel.
No point doing another review as such, most of it was done in the previous video. So it would be looking at what they have changed and maybe some thermal and load tests etc.

Dave.

[Uncle Vernon]

So it would be looking at what they have changed

That would be the point of interest. Whether the degree of change warrants another video is your call.  Are these pieces of wonder a stock item at Trio again? I've seen no mention of them since removal?

[EEVblog]

Are these pieces of wonder a stock item at Trio again? I've seen no mention of them since removal?

No, Charles is still waiting for replacement boards for the existing units he has in stock.

Dave.

[Bored@Work]

...

You know, in the US they sometimes say someone is two fries short of a happy meal. I think you are two test leads short of a multimeter. And two shrimp short of a barbie , if you get the drift.

[rr100]

My enthusiasm for a new video is almost zip.
But if people really want a follow-up, I might put it on the list.

I'm interested, if we are to prioritize just behind the USB/portable/etc power supply progress report (assuming there is some progress).

Of course, all of them are coming behind the vids with Colin Mitchell and Doug Ford, but I assume those just one-off sort of things.

[Uncle Vernon]

You know

Maybe, but you're going to tell me right?

in the US they sometimes say ........

That is nice for them! In Borneo folks likely say something entirely different

I think you are

There is your mistake, you've kidded yourself that others, let alone my good self five a flying fourex what you think. 
Was it one of your flying generalisations like "all Asians are thieves" or some other manic rambling? You can answer if ou like just don't assume anyone is listening. 

We can reasonably conclude you have nothing of use or interest to offer on this topic.. 

[EEVblog]

Of course, all of them are coming behind the vids with Colin Mitchell and Doug Ford, but I assume those just one-off sort of things.

Colin was a one-off, he's in another state.
Doug will be back with a quite a few episodes.

Dave.

[Bored@Work]

...

Could you at least be a bit original and funny? I mean, just for once? Repeated racism accusations? How boring.

[Uncle Vernon]

Could you at least be a bit original

For you? Lemme see? Na, Nup, nada, not worth it! 

and funny?

What you're not laughing? Must be taking yourself seriously again. That gives others a giggle and for that we thank you. 

Repeated racism accusations?

must be in response to repeated racism. hmm?