That looks worse than the KORAD. Also BK Precision re-badge other products, like the Siglent Scopes, the Atten spec-an, Protek HH-spec-an and some of the power supplies look similar to those on Extech's website. It would be great of someone started a cross-reference for all this re-branding nonsense so we can buy from the OEM and cut-out the big-name companies adding the brand name and price tag. As for Alexei's power supply, does it say "made in China on the back panel?"
Greetings and thanks for all the feedback.
Firstly yes we have withdrawn this from sale until we get to the bottom of the failure. To answer the previous question about what process do we use to decide what to sell, well we have a process and this passed it.
We got two samples a 30V 5A and a 60V 2A. As an ISO-9001:2008 accredited company,
The samples do get pulled apart. For example the white residue on the boards was known to us, we've seen it on more than one suppliers' boards and it has never been a reliability issue.
Can we skip that ISO thing, please?
Would of course be nice if Korad released the schematic!
Time to change your process to apply a more conservative pass criteria?
Can we skip that ISO thing, please? After decades in the industry, taking part in multiple accreditations, and having had to game the system daily for long periods of time I have nothing good to say about it.
QuoteThe samples do get pulled apart. For example the white residue on the boards was known to us, we've seen it on more than one suppliers' boards and it has never been a reliability issue.
The thing with the flux residue is you can't know its long term effects, e.g. if that particular residue is corosive<sic> over time. You just don't know the manufacturing process and what they used.
And lets just say, as a calibration company you should have got very, VERY nervous about that DAC. That is your core bussines.<sic>
Can we skip that ISO thing, please? After decades in the industry, taking part in multiple accreditations, and having had to game the system daily for long periods of time I have nothing good to say about it.Why? It the tool of delight for desk cowboys like yourself. A long winded way of saying all care, no responsibility.
I disagree with Mr. Bored not having much good to say about ISO, many others do have good things to say and look for ISO accredited vendors. It forces a process and a standard on to a company. Agreed that compliance is a pain in the a$$ but it sets a level people can judge a company by.
As for Alexei's power supply, does it say "made in China on the back panel?"
Mind you I agree on the testing process, perhaps more a few more real world operational tests in addition to a cal-lab performance verification might uncover this sort of thing before Dave gets his hands on it. I think they sell electronic loads too so maybe they should test both together ;-). Probably though a batch test would be the way to go when something like this is uncovered to see if Dave got the lemon or a normal product.
No opinion on the DAC really, if it does its job as Dave says what the heck!!! I hope Dave does a tear-down to find the problem with it. Anyone want to start a poll to guess the fault?
What you received was the early delivery and in this delivery, there is something wrong with those transistors. And we have improved since that shipment.
As for 60V, 2A, the transistor on it is good. Don't worry. And this won't happen again.
Official response from Korad (in part):QuoteWhat you received was the early delivery and in this delivery, there is something wrong with those transistors. And we have improved since that shipment.QuoteAs for 60V, 2A, the transistor on it is good. Don't worry. And this won't happen again.
So there you go, under specced (or dodgy) transistors, surprise, surprise!
Genuine high power transistors are not cheap, and have been scammed on the grey market for several decades now. Wouldn't surprise me if Korad got duped.
Dave.
Official response from Korad (in part):QuoteWhat you received was the early delivery and in this delivery, there is something wrong with those transistors. And we have improved since that shipment.QuoteAs for 60V, 2A, the transistor on it is good. Don't worry. And this won't happen again.
So there you go, under specced (or dodgy) transistors, surprise, surprise!
Genuine high power transistors are not cheap, and have been scammed on the grey market for several decades now. Wouldn't surprise me if Korad got duped.
Dave.
Hmm dodgy vendor selling gear with dodgy parts from who knows where. With something like a PSU that can deliver so much power, that is literally asking for lawsuit when it blows up in someone's face ...
Well, yeah, pre production models can fail. You had the Agilent scope also failing with the extension card board. They fixed the issue and now it works fine. So I guess it happens all over the industry.
Well, yeah, pre production models can fail. You had the Agilent scope also failing with the extension card board. They fixed the issue and now it works fine. So I guess it happens all over the industry.
Just on my blog alone there is the Agilent 3000 scope, the Extech 505 meter, the Extech pen meter, the BK Precision LCR meter, and the Agilent U1272A meter (any others?)
So yeah, it happens all the time. Most are never made public.
Dave.
I disagree with Mr. Bored not having much good to say about ISO, many others do have good things to say and look for ISO accredited vendors. It forces a process and a standard on to a company. Agreed that compliance is a pain in the a$$ but it sets a level people can judge a company by.
But it simply comes down to the question " is the procedure relevant and beneficial to your business and will your customers benefit because you have these processes?" We believe it does.
Very bad failure mode. It should fail with a fuse blown or 0V output. If they had a ~36V TVS on the output the worst case would be a blown fuse. But no... There's a reason I prefer an old surplus PSU to a new crappy one...
Official response from Korad (in part):QuoteWhat you received was the early delivery and in this delivery, there is something wrong with those transistors. And we have improved since that shipment.