Author Topic: Korad KA3005P power supply: UI changes  (Read 13382 times)

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Offline bateau020

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Re: Korad KA3005P power supply: UI changes
« Reply #25 on: April 21, 2022, 08:31:23 pm »
Early KA3005P units like mine at home have a very different heatsink from later units, one that causes far more turbulent airflow. Replacing the fan in those (which I did in mine) does improve noise, but not by very much. It’s my understanding that the new heatsink design is much quieter.
Not only that. Mine (and probably also yours, many versions exist though) uses a fairly low frequency PWM to drive the fan, making it jitter. Hence the noise.
Adding a cap in // to the fan lowers the noise a lot, and is easy to do.
I however just installed an independent temperature driven fan driver circuit and replaced the fans with quieter 4 pin PWM fans. Completely silent now, unless I drive the PSU hard. And even then, it is still a lot better than before.
 
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Offline MikeK

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Re: Korad KA3005P power supply: UI changes
« Reply #26 on: April 22, 2022, 01:51:02 pm »
I however just installed an independent temperature driven fan driver circuit and replaced the fans with quieter 4 pin PWM fans. Completely silent now, unless I drive the PSU hard. And even then, it is still a lot better than before.

Are you using an NTC thermistor and an 8-pin uC?
 

Offline bateau020

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Re: Korad KA3005P power supply: UI changes
« Reply #27 on: April 22, 2022, 02:48:43 pm »
Even cheaper: one of the many temp controlled fan controller boards from aliexpress. I used a dual controller, since I have the 2 channel version of the PSU. But many single channel versions also exist. Took the power from one of the cables going to the front panel (18V AC? if I remember right), created the controller board power via a buck converter (you guess where I got the latter) and mounted it all on a bracket. For some things buying is cheaper than building.
 

Offline MikeK

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Re: Korad KA3005P power supply: UI changes
« Reply #28 on: April 22, 2022, 03:12:04 pm »
Is the fan controller board using a uC?  I may make this mod to my PS, but I'd rather not have a uC that could fail and cause overheating.  (We all make coding mistakes.)   I'm thinking an NTC and comparator.
 

Offline bateau020

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Re: Korad KA3005P power supply: UI changes
« Reply #29 on: April 22, 2022, 03:19:36 pm »
There are specialised chips for fan controlling, but an attiny214 for example could also do it. Github has some fan controller projects. Just use the watchdog or do repeated resets. If you want more security, you could add a comparator and a buzzer or relay for example.

edit: or you could use a standard thermal fuse that you place in the mains line.
« Last Edit: April 22, 2022, 03:22:52 pm by bateau020 »
 

Offline Geoff-AU

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Re: Korad KA3005P power supply: UI changes
« Reply #30 on: May 24, 2022, 12:28:01 am »
Have 2 re-badged versions of these.   One is very finicky in flicking voltage values up down when using the wheel to adjust voltage (adjst voltage of current).   It can flick up/down wildly with minor encoder wheel movement.   Its is extremely annoying.     Mainly noted when adjusting points of a volt/current.

I have 2 of them...the other is ok but a little twitchy like the first.

Its as if its not counting the encoder correctly or makes multiple jumps on one encoder click.  Going to have to try fix this....real PITA.

Replace the rotary encoder.  It's a bit of digging to access it but highly worthwhile.  The original encoder contacts go intermittent and that can cause all sorts of fun things, like trying to reduce the voltage and having it shoot up by 6 or 7 volts.  Certainly enough to fry a board if you are doing it "live".  I have the dual supply and replaced rotary on both sides, working perfectly again now.

 

Offline LinuxHata

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Re: Korad KA3005P power supply: UI changes
« Reply #31 on: May 25, 2022, 04:52:21 am »
Interesting, is it possible to extract firmware from the new version and flash it into old version?
By the way, I also have this PSU and did a "triple" mod, to make it far less noisy.
1. Fan is replaced with a far more silent version. Made by Nidec.
2. Fan is mounted onto silicone rubber padding, to reduce vibration noise
3. heatsink is not mounted on fan any more, so it can't transfer fan noise onto main body.

If anyone wants to skip all this and just have "Korad" grade PSU, but without noise, without short timeout and other issues, I suggest you to buy eTOMMENS eTM-305DP. It is basically same as this Korad, but has different fan management system (fan is off in most cases), fan is less noisy, and issue with knob timeout is solved too. Also, there's a service menu, which can be accessed by holding output enable button, while powering unit on. You can adjust beep on/off, calibrate meters and many other things from that menu.
 

Offline Pfriemler

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Re: Korad KA3005P power supply: UI changes
« Reply #32 on: January 11, 2023, 09:54:54 pm »
Sorry for rehashing the thread....
Just got my KA3005+ from Welectron (the screw terminals are sold out by the way). These are my results from a first test:

  • the Korad always starts with the settings in M1 (don't know if this is new or not).
  • whenever you change a value after calling a setting from M1..M4, the corresponding M1..M4 LED stops lighting. The memory setting is not updated until I long press the Mx button
  • A short press on [LOCK] still provides an easy way to change the voltage OR the current (whichever was set last), selecting the digit to be changed with <- or -> as usual.
    The digit remains blinking, as long as the output is off.
    If output is on, the blinking stops after a few seconds.
    the digit to be set changes to 1/10V and 10mA if it was set to 1V/0.1A or 10V/1A. If the "cursor" was on 10mV/1mA, it remains there. This could be useful to avoid big changes by accident, but keeps possible small adjustment as long as this mode is active.
    The dot in the most right digit blinks as long as this mode ist active.

Do I have a newer version? "*IDN?" answer is "KORAD KA3005P V5.8 SN:03203xxx" (dunno if the serial is secret)
edit: corrections of list, version information
edit2: correction of behaviour

« Last Edit: January 18, 2023, 03:46:00 pm by Pfriemler »
once you do it right, it works :-)
 

Online ebastlerTopic starter

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Re: Korad KA3005P power supply: UI changes
« Reply #33 on: January 12, 2023, 06:21:55 am »
Yes, that must definitely be a new version! The memory behavior you describe in your second bullet (long press required to store changes) implements a long-requested change. As stated in my original post in this thread, the version I received in April 2021 still changed the memory values as soon as you changed a setting.

I must say I'm impressed that Korad continues to listen to user feedback and make improvements to this older, low-cost product. (Although they are taking their time...)

The "always starts at M1 on power-up" behavior is unchanged from prior versions. The automatic jump to 1/10V or 1/100 A in "permanent adjustment" mode is new, I believe -- and I am not sure whether that one is an improvement?
 

Offline Pfriemler

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Re: Korad KA3005P power supply: UI changes
« Reply #34 on: January 12, 2023, 04:55:48 pm »
eBastler* what's your FW version?
Yes, I was surprised by these news in behavior - it is as you will expect it, regarding the memories. And to store safe values to M1 is easy. I like it much more than returning to the last settings after power off. My Matrix MPS3206 is very special in this...

I think, the 1/10V as default is rather not that what most users will like.
once you do it right, it works :-)
 

Online ebastlerTopic starter

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Re: Korad KA3005P power supply: UI changes
« Reply #35 on: January 12, 2023, 06:23:01 pm »
My two KA3005P's are on firmware version 5.5, they say.

I double-checked the behavior of the permanent adjustment mode while I was at it. After a short press on LOCK, I can select current or voltage and select a digit, and then the adjustment mode will happily stay on that digit forever. (Unless I change it again via the <> buttons, of course.) The adjustable digit also keeps flashing at 1 Hz, which is a bit obtrusive but provides a clear visual reminder that the adjustment knob is active and will affect this digit.

Time for version 5.9, which combines the new memory behavior and the old permanent adjustment mode. ;)  Ah well, we will most likely never get firmware upgrades for the existing units. Nevertheless, kudos to Korad for continuing to make improvements!
« Last Edit: January 13, 2023, 07:42:40 am by ebastler »
 

Offline Pfriemler

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Re: Korad KA3005P power supply: UI changes
« Reply #36 on: January 18, 2023, 03:57:26 pm »
... KA3005P's on firmware version 5.5 ... After a short press on LOCK, I can select current or voltage and select a digit, ...
The adjustable digit also keeps flashing at 1 Hz, which is a bit obtrusive but provides a clear visual reminder that the adjustment knob is active and will affect this digit.
I just took a deeper look at mine @ FW5.8: The digit remains blinking as long as the output is off. But the "instant change mode" isn't active yet (if output is off), but the dot is on, if you press [LOCK].
If output is on, the blinking stops after a few seconds.
And now:
The (now invisible) cursor remains at 100mV/10mA and 10mV/1mA. Small adjustments are still possible! Only if the cursor was on 1V/100mA or 10V/1A, it jumps back to 100mV/10mA.
The just changed digit blinks as usual and stops blinking after a few seconds.
As long as (esp. in current changing mode) a digit blinks, the display shows the "set" value, if nothing blinks, the measured value.

My post above is corrected.

With this, I am very happy. The activated "permanent adjustment mode" is more safe, the risk of (too) big steps is reduced, small adjustments are not affected.

« Last Edit: January 18, 2023, 04:01:53 pm by Pfriemler »
once you do it right, it works :-)
 
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Offline smallfreak

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Re: Korad KA3005P power supply: UI changes
« Reply #37 on: April 25, 2023, 09:15:46 pm »
I'm curious. Are there still two different models of this PSU available or are meanwhile all of them the "plus" version with the green voltage display and a "lock" indicator instead of an M5?

Welectron lists them as separate but also lists all of them as "not available" so this does not necessarily mean that the "non plus" versions will ever become available again. Everyone else still shows the "all red/M5 LED" images but I doubt that Korad would keep two nearly identical models in production.
 

Offline IvanBayan

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Re: Korad KA3005P power supply: UI changes
« Reply #38 on: May 31, 2023, 12:16:19 am »
It's turned out that one more revision or similar version exist, it's called KKG305P.
The main announced differences: it has wattage display, solid state relays instead of regular (at least I can't hear clicking), external sense input, external trigger/switch input and RS487+Modbus.
I've managed to bought one. The most interesting thing that you can't find it on official Korad's web page.
I asked them via email about differences with KA300P and got the next answer "KKG305P is our KORAD product. We will put it on the website later. And KKG305P has more functions, higher performance and better quality than KA3005P."
 

Online ebastlerTopic starter

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Re: Korad KA3005P power supply: UI changes
« Reply #39 on: May 31, 2023, 05:37:20 am »
Hey, and there is a "Set" button! Which hopefully means that the M1..M5 presets will only be changed (and stored) if one explicitly requests that by pressing "Set"?
 

Offline Pfriemler

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Re: Korad KA3005P power supply: UI changes
« Reply #40 on: May 31, 2023, 03:48:56 pm »
It's turned out that one more revision or similar version exist, it's called KKG305P.
Please remember the thread title: UI changes in KA3005P.

The KKG305P is a complete new and different device (even a KD3005 is not comparable to the KA3005) and it's definitely worth a new thread here.

Hey, and there is a "Set" button! Which hopefully means that the M1..M5 presets will only be changed (and stored) if one explicitly requests that by pressing "Set"?
With my (new) KA3005P, M1..M4 (no M5, LED shows the LOCK button status), no settings are changed by accident, only by a long button pressure. M1 is recalled during power up and should be programmed with safe values. I love this behavior.
« Last Edit: May 31, 2023, 03:51:09 pm by Pfriemler »
once you do it right, it works :-)
 

Offline ddrl46

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Re: Korad KA3005P power supply: UI changes
« Reply #41 on: May 31, 2023, 08:06:27 pm »
It appears that another variant has shown up, the KA3005PS / KA3005PEA.



 

Offline Pfriemler

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Re: Korad KA3005P power supply: UI changes
« Reply #42 on: May 31, 2023, 08:57:23 pm »
Both are listet @ Eleshop.eu. Low noise fan, better amps resolution, PEA with external on/off and sense.

Main specs same as KA3005P. Maybe I am wrong and these devices are ideed new housings with basically the same power circuits.
But SSR replacing the relays ... is this a good idea at all?
once you do it right, it works :-)
 

Online ebastlerTopic starter

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Re: Korad KA3005P power supply: UI changes
« Reply #43 on: May 31, 2023, 09:17:44 pm »
From a UI perspective, I am disappointed that Korad did not switch to translucent rubber buttons with the indicator LEDs back-illuminating each button. That can't be significantly more expensive than the current setup, and would make it so much more obvious which indicator maps to which function button.
 
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Offline 5U4GB

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Re: Korad KA3005P power supply: UI changes
« Reply #44 on: February 03, 2024, 09:47:07 am »
Under light load the fan is very quiet -- much less audible than my Siglent SDG2042X, which in turn is much quieter than the Rigol DS1000Z scope. When I short the outputs in the 30V/5A setting, the fan gets cranked up gradually and does become louder than the Rigol -- but I can still tell whether the Rigol fan is on or off, it does not get drowned out.

Just got a 3005D (not P) which is dated December 2022 and this also has the updates described here, but not the case colour change.  I'll post a link to a teardown a bit later on, but one thing I noticed is that the fan only has two wires and no sense wire, so the reason why the ramp up is slow could be because the control software has no idea what speed the fan is running at and has to just gradually ramp it up and see what the HS temperature changes to.

In general though the heatsink layout is pretty strange both for the original and updated heatsink, instead of the air flowing across the fins the HS is mostly blocking the air flow, which I would imagine leads to both poor performance and a lot of unnecessary noise because there's a solid block of metal a few cm from the blades.  What were they thinking?
 

Online ebastlerTopic starter

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Re: Korad KA3005P power supply: UI changes
« Reply #45 on: February 03, 2024, 09:58:06 am »
In general though the heatsink layout is pretty strange both for the original and updated heatsink, instead of the air flowing across the fins the HS is mostly blocking the air flow, which I would imagine leads to both poor performance and a lot of unnecessary noise because there's a solid block of metal a few cm from the blades.  What were they thinking?

That less-than-ideal arrangement probably dates back to the first generation of KA3005s. Those did not have a proper heatsink with fins at all, but essentially a flat aluminium plate with some token "fingers" along the edges, made by cutting and bending the plate. Blast some air straight onto the plate, done.  ::)

Can be seen in Dave's original teardown video from 2013: https://youtu.be/g94mpom2Ahs
 

Offline 5U4GB

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Re: Korad KA3005P power supply: UI changes
« Reply #46 on: February 03, 2024, 10:13:24 am »
Yeah, and you can't easily change it because they're replaced the fake Rubycons with a single giant cap that would get in the way of the transformer if you rotated it 90 degrees to allow flow down the vanes:



You'd also, because of the metal plate to force airflow across the transformer, get very poor airflow across the heatsink.
 

Offline 5U4GB

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Re: Korad KA3005P power supply: UI changes
« Reply #47 on: February 03, 2024, 11:44:23 am »
Just posted a bunch of photos and comments of whatever version it is they're shipping now.
 
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Offline Pfriemler

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Re: Korad KA3005P power supply: UI changes
« Reply #48 on: February 03, 2024, 02:45:57 pm »
Well, as far as I remember there was a single main cap all the time, even in the first version Dave teared down.

I do think different to the fan behaviour: Unlike any PC stuff with monitoring hardware, a tacho signal from the fan is rather seldom in such hardware and even a PWM controlled (4 wire) fan is a kind of overkill to such a device. The Korad does not have to know about the speed of the fan, as long as there's a sufficent correlation between rotation speed and the supplied voltage - which is the case, normally.

And for the air flow design: If you place a fan this way directly above the heat sink, you have a powerful airflow through the cooler even in the direction of suction, as here. The cooling would be better if you change the air direction as suggested by some users, but I would never heat the components inside this unnecessary way.

Ramping speed may come from the fan regulation. Unlike the first versions with a load regulated fan speed the cooler follows the load with a load dependent delay, very normal. I remember my Voltcraft DPS2010, famous for a stupid fan regulation: the fan starts at about 42 °C and reaches may speed @ 50 °C, regulation far too steep, which results in an oscillating speed of the fan with middle loads. And, full fan speed with any current >40% of maximum. That's annoying!

As mentioned above, I have a new Welectron design model and got me another second hand, RND 320 KA3005P, answering "V5.5" on *IDN?. I have no idea how long this version is on market (and how old it is). Now I can compare both versions in behaviour and performance and do like the improvements a bit more. At a first glance, the fan speed at no load is significantly lower with the new version.

Next week I will make a "light teardown" of both to examine differences, before I go and fix the non lit OVP and OCP LEDs and the (sometimes) snarring fan.

« Last Edit: February 03, 2024, 02:48:46 pm by Pfriemler »
once you do it right, it works :-)
 
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Offline Pfriemler

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Re: Korad KA3005P power supply: UI changes
« Reply #49 on: February 05, 2024, 08:58:04 pm »
Hard to believe: both OVP and OCP status LEDs were dead. Because I wanted to change C.V. and output LED, I got two spare LEDs and solder them to OCP and OVP. After that, the third LED was broken.
Btw. the LEDs are of a dedicate low current type. They need not more than 3 mA for full brightness.

The differences of both RND (Reichelt) KA3005P V5.5 and KORAD (Welectron) V5.8 are only a few:
- there was no metal sheet inside above the transformer
- the com board looks complete different
The red/green led board and the housing color are obvious.

To my very surprise, there's no difference in fan control. Both uses 120 Hz PWM, I got no differences with the scope. But the fan seems to be different in sound as well as in air flow. I even put both devices side by side and let them power the opposite's fan - the Welectron's one stays more quiet.
If I stress both versions with a 5 amps full short circuit, the semiconductors on power board heat up to ~110°C, sometimes with a 2-3 degrees difference, so there's no lack n cooling under load.
Also the sound measurements show a rather light difference under full load (49 vs 51 dBC) and idle (34 vs 38 dBC, ~1m distance, back side, yet no housings)


once you do it right, it works :-)
 


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