Korad KA3005P power supply: UI changes

[ebastler]

Just a quick update on this popular low-cost power supply: I just received one of these, ordered via Welectron in Germany, after a long wait for a new shipment to arrive from China. Compared to what I have seen in videos and written reviews, Korad have made some improvements to the user interface:

• The M5 LED (5th memory, which did not have its own key anyway) has been replaced by a LOCK LED. I believe this was in the original version too, and at some point got replaced by the M5 LED.
  
• Significant improvement: A short press of the "Lock" button enters a mode where you can adjust voltage or current via the encoder and arrow buttons without any timeout. There were many complaints about the short timeout in earlier versions. To lock and unlock the keypad, a long press on Lock is needed.
• Unchanged: The behavior of the "memory" buttons. Any change to the current or voltage setting will immediately change that memory preset.
• Changed? It is easy to accidentally tap one of the M1..M4 buttons and set the Korad to a different output voltage. But it automatically switches its output OFF whenever you switch to a differen memory preset, so you don't fry your load. Not sure whether this behavior is new? I don't recall seeing it mentioned, but have not watched out for it in the reviews.
• Cosmetics: The sheet metal enclosure is now charcoal-colored. The 7-segment display for voltage is green, current display is red. The status LEDs for "ON" and "constant voltage" are green, the others remain red.
• My KA3005P still came with binding posts (with standard pitch), not the stupid safety jacks shown in some photos. Nice!

Overall, I am happy to see that Korad continues to make incremental improvements to this product. I have not looked inside and have not measured any output behavior yet. Let's hope that they did not change anything for the worse!

[YurkshireLad]

Is there any way to tell which version a vendor is selling? Or is it a crap shoot (except for physical changes to the exterior)?

[hexreader]

You forgot to mention the feature that this PSU is (in)famous for.

Is the fan any quieter?

I live near an airport and I would like to be able to hear the military jets taking off with full after-burners - without the Korad fan noise drowning them out 

[MikeK]

• Unchanged: The behavior of the "memory" buttons. Any change to the current or voltage setting will immediately change that memory preset.

This one is very annoying.  And at odds with common sense and proper behavior.  Essentially, you have to give up one of the presets so that it can become the "current setting".  "Current" meaning time, not electricity.

If I manually tune the radio in my car it doesn't change the presets.  Nor should it!  Changing the power supply preset should be just like the car radio...long press to save.

[ebastler]

Is there any way to tell which version a vendor is selling? Or is it a crap shoot (except for physical changes to the exterior)?

The model number is unchanged, KA3005P, and I would not trust the vendors to update the pictures on their websites. So I would specifically ask the vendor about the changes which are visible externally -- the "LOCK" instead of "M5" label on the LED is visible with the unit turned off, and the green digits for the voltage are obvious when it is turned on.

Is the fan any quieter?

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.

The noise one hears under load is from the airflow, not from the fan bearing, and is not unpleasant in pitch to my ears. The fan speed control is temperature-dependent, not simply derived from the voltage/current draw. It is not "nervous" but ramps up and down gradually. Hence I would say Korad did a decent job within the constraints of the fan size.

This one [memory button behavior] is very annoying.  And at odds with common sense and proper behavior.  Essentially, you have to give up one of the presets so that it can become the "current setting".  "Current" meaning time, not electricity.

If I manually tune the radio in my car it doesn't change the presets.  Nor should it!  Changing the power supply preset should be just like the car radio...long press to save.

Yes, that one is a disappointment. Seems that it would have been very easy to improve via a software change -- e.g. by requiring a long press of a memory button to save the current setting to it. Maybe next year... ;-)

[ebastler]

Turns out that even Korad has not gotten around to changing the product description on their website,
http://www.koradtechnology.com/product/14.html. For reference, the attached photo shows what my new unit looks like -- note the green LEDs, LOCK LED and the dark case.

I assume the LOCK LED was brought back to better support the extended behavior of the LOCK button: long press to lock the keypad, short press to get to "continuous adjustment" mode. I like the changes they made and the (unchanged) compact package. Got a second unit on order!

[masterx81]

On my 3305 the most annoying thing is the really small timeout of the adjustments, nice that they are starting to fix it on the single units.

[MikeK]

Even nicer would be the source code so that people who actually use it can develop the proper firmware. 

[ebastler]

Even nicer would be the source code so that people who actually use it can develop the proper firmware. 

I assume they intentionally keep the lid on the software to discourage even-lower-cost competitors from copying it. More likely than not even the binary is read-protected inside its microcontroller?

But the software as it stands is quite usable in my view. My only remaining wish would be a different behavior of the memory buttons -- short press to recall, long press to store a setting or something along those lines.

[MikeK]

For reference, the attached photo shows what my new unit looks like -- note the green LEDs, LOCK LED and the dark case.

I think yours is a revision newer than mine, which was purchased from Amazon in October 2020.  All of my LEDs are red.  They may have taken a cue from a YouTube mod to change the output LED...a change I plan to make eventually.  I would like to see OVP/OVC as one color, CC/CV another, and OUT a third color.  At the very least I want OUT to be different than all other colors.  Have you imaged the inside?

[ebastler]

Have you imaged the inside?

I have briefly looked inside to check for proper grounding, but have not taken any pictures, sorry. I'll open it again and add some photos here over the next couple of days.  All nice and tidy on the inside; in addition to the cable ties and tidy routing I knew from photos, I noticed that they have secured all plugs with some white glue (presumably removable...).

The only thing that struck me as strange was that the power PCB attached to the heatsink is actually comprised of two PCBs sitting next to each other. Each pretty exactly half the size of the heatsink, mounted by two shared screws in the middle plus separate screws near the outer edges. The leads from the transistors (?) on one PCB were soldered to both PCBs to contact them, if I saw that correctly. Not sure what cost-savings or reliabilty improvement that is meant to bring?? I will look more closely and try to get photos of this part too.

[MikeK]

The only thing that struck me as strange was that the power PCB attached to the heatsink is actually comprised of two PCBs sitting next to each other. Each pretty exactly half the size of the heatsink, mounted by two shared screws in the middle plus separate screws near the outer edges. The leads from the transistors (?) on one PCB were soldered to both PCBs to contact them, if I saw that correctly.

Yep, mine's the same:

[ebastler]

Yep, mine's the same:

Many thanks for the pictures! Yes, exactly the same in mine, including the elegant two-tone look of the PCB in black and green. 
Same glue on the plugs as well. So it seems that they only changed the LED colors and the firmware in the most recent revision.

[YurkshireLad]

It just occurred to me that this KA3005D has the LOCK LED. Does that make this one an original version or an updated version? Or did the KA3005D always have it? Confusing.

https://www.amazon.ca/dp/B0084JFWNY/

[ebastler]

It just occurred to me that this KA3005D has the LOCK LED. Does that make this one an original version or an updated version? Or did the KA3005D always have it? Confusing.

https://www.amazon.ca/dp/B0084JFWNY/

As mentioned in the original post above, I believe the KA3000 series originally started out with the LOCK LED. Then at some point Korad thought it would be a good idea to offer the 5th memory -- without adding a 5th button for it, hence the awkward way of addressing it indirectly via the encoder. Most recently, with the introduction of the overloaded LOCK button (short and long press), having a clear indication for the LOCKed status became more important again; so they dropped the 5th memory and went back to a LOCK LED.

I guess the picture in that Amazon offer shows a very early version of the power supply, since it does not have the green display. I have seen these pictures occasionally, also in some of the old instruction PDFs that float around on the 'net. It's probably not the exact version they ship; unless they have very recently received new stock you would likely still get a unit with the "M5" LED.

But hey, it's "Certified frustration-free" according to the seller, so what could possibly go wrong?

[ebastler]

One more update: I just received the second unit I had ordered after being pleasantly surprised by the first one. Number two has a slightly less pleasant fan; I can hear what seems to be a little bearing noise. Nothing terrible, no rattling or such, it sound like just a bit of extra friction. So far my "solution" is simply to place the two units next to each other on the shelf such that the quieter one is closer to me...

Controls and LEDs are exactly the same on both units, as one would expect.

[NeonTron]

Can you please post a picture of the back of the unit? I'm wondering if the black case model from Welectron can handle 110V input. The version on Amazon seems capable of being switched between 110V and 220V (see attached picture).

[ebastler]

The updated Korad version I received from Welectron is labelled for 230V, and does not have a selection switch for the mains voltage -- just like the earlier version.

Unfortunately there is no easy way to re-wire the transformer primary windings inside the unit either: Only two wires are brought out from the transformer, not two separate primary windings which one could wire either in series or parallel. (See the attached photo -- mains jack on the left, power switch on the right.) It seems that Korad actually installs different transformers in the 230V vs. 110V versions.

[eevblogger88]

One more update: I just received the second unit I had ordered after being pleasantly surprised by the first one. Number two has a slightly less pleasant fan; I can hear what seems to be a little bearing noise. Nothing terrible, no rattling or such, it sound like just a bit of extra friction. So far my "solution" is simply to place the two units next to each other on the shelf such that the quieter one is closer to me...

Controls and LEDs are exactly the same on both units, as one would expect.

What's the most quiet fan that you can recommend to change the stock one in the Konrad?

[ebastler]

What's the most quiet fan that you can recommend to change the stock one in the Konrad?

I don't have personal experience replacing the fan; I am still running the stock fans on both my units. Any 80 mm * 25 mm fan rated at 12V should work in principle.

If you Google "korad ka3005p fan replacement" you will find various Youtube videos showing fan replacements. Artic Cooling F8, Noctua NF R8, and some Panaflo brushless fan are mentioned as replacements there. I think all of them come with a different plug than the one used in the Korad supply, so you will have to swap out the plug or get an adapter.

Having said that -- are you already using a KA3005P, and have confirmed that the fan noise is an issue for you? I would definitely test-drive it for a while; as mentioned, I found that I don't mind the fan.

Edit: Fixed typo in the model number; the KA3005P (with USB/serial interface) is the most popular model, and the one discussed  here.

[MikeK]

are you already using a KA3005D, and have confirmed that the fan noise is an issue for you? I would definitely test-drive it for a while; as mentioned, I found that I don't mind the fan.

I agree with ebastler.  The fan in my Korad is not noisy at all.  If you do need to replace it, I put a Noctua NF-A6x25 FLX in my [formerly noisy] Rigol DS1052E oscilloscope and it is pleasantly quiet.  I'm not saying it fits the Korad PS (I don't know), but I'm at least recommending the brand.

[ebastler]

@eevblogger88, one more comment. I just saw from your other posts that you are in the process of setting up an electronics bench from scratch, intending to do repair work on phones and computers.

Do you plan to do that for money, by repairing for others and/or making Youtube videos? If so, have you been able to gain some practical experience yet? Watching Youtube videos by Rossman and Northridgefix and buying a bunch of equipment is not the best approach to become productive, I think.

E.g. it would be so much better to try working with a binocular microscope vs. a video microscope yourself, rather than listening to what the guy at Northridgefix prefers. (I don't doubt he knows what he is doing, but what works for you will strongly depend on personal preference and experience!)

If you have not done so yet, and have any opportunity to make it happen, I would recommend that you look for an internship in a repair shop.

[tooki]

are you already using a KA3005D, and have confirmed that the fan noise is an issue for you? I would definitely test-drive it for a while; as mentioned, I found that I don't mind the fan.

I agree with ebastler.  The fan in my Korad is not noisy at all.

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.
I have a recent KA3005D at work and it’s noticeably quieter.

[MikeK]

Since this thread is about UI changes, I want the memory buttons and the indicators (LEDs) in the same bloody place.  Either put the LED right next to the button, or inside the button.

[wasyoungonce]

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.