Bench power supplies

[bitseeker]

Then after a little bit more messing with the knobs and buttons the problem went away completely.

That is a weird problem. Maybe a firmware bug where it gets into an unexpected state? Glad you got it to finally behave. It'd be nice to know at least the steps to fix it when it acts up.

[bitseeker]

I've got  KORAD KA3005D-3S (dual 30V/5A with serial/parallel mode + constant 5V/3A)  some time ago and I'm very happy with it (only problem was a bit shoddy power switch but that is easy enough to replace), but it seems it is not available anymore? Did they stopped producing it ?

If I remember correctly, the KA3305D is the model that came after it. The "-3" got moved to the beginning of the model number and the extra 0 went away. 3-channel, 30V, 5A -> 3305.

[jasonbay13]

so after using it a while, its still working fine. use it almost every day
i wanted to mention that the cables it comes with are not so great. sure they work, but are of ebay quality. i measured over half a volt drop just through the wires at 5A. i made up a pair and soldered the connections. at the same 5A i got less than 50mv drop.

[Vtile]

Oh... Didn't notice you have your new PSU now. 

[james_s]

I've always built my own power supplies, they make good beginner projects and they are useful for all manner of other projects. These days you can take the easy route and reuse an old laptop power brick or similar and one of any number of regulator modules you can buy from Chinese suppliers these days.

[pete1zed]

I bought the TENMA 72-10495 (AKA Korad KA3005D-2S) dual channel power supply, but there are many issues with it.  To help others understand it's limitations before buying it (or to help work out its insane user interface after purchase),
here is the manual, marked up with corrections and warnings about bugs in the user interface and behaviour:
https://ufile.io/drsjx09j

This applies to models:
 - TENMA 72-10495 (Korad KA3005D-2S):  30V-5A x 2 Channels
 - TENMA 72-10500 (Korad KA3003D-2S):  30V-3A x 2 Channels
and probably also
 - TENMA 72-10505 (Korad KA3003D-3S):  30V-3A x 2 Channels & 5V-3A x 1

Important notes to avoid damage:
●   Do not allow power supply to sink current.  Use diode when charging battery.
●   For sensitive circuits, see Avoiding overshoot and excessive in-rush current :
  ○   Inside the power supply, there is a capacitor near the output terminals for stability.  The current limiting and over current
        protection (OCP) cannot control current from this capacitor. 
  ○   There is some overshoot on turning a channel on.
  ○   There is a spike when turning mains off while the channel is on.
●   In parallel mode, connect load to CH2 (right hand) channel.  (When mains power is turned on, the power supply defaults to
        independent mode, and CH1 to whatever voltage and current settings are in CH1 memory recall M1, with the load turned off.
        Therefore, avoiding CH1 could prevent mistakenly applying wrong settings to the load.)
●   OCP and OVP do not work in serial and parallel modes.
●   If you recall a CH2 memory in SER mode, only CH2 is updated from that memory and only CH2 turns off.  At this time, CH2
        output terminals have up to -1.2 V (i.e. reverse polarity) on them, with a short circuit current of up to -2.8 A. 
       This also happens when the channels are independent but you have wired them in series. 
●      When using the power supply in SER mode, or wired in series, you may have to ensure the supply is working in CV mode to
        avoid instability. 

   
Important notes to avoid confusion:
●   There is a small negative voltage and current when the load is switched off (50mV, 100 uA)
●   OCP/OVP:
  ○   CH2 OUT LED stays on after CH2 OCP/OVP trip disconnects the load.
  ○   OCP and OVP do not work in serial and parallel modes
  ○   CH2 OVP/OCP buttons also control CH1 OVP/OCP
  ○   CH1 OVP/OCP buttons only control CH1 OVP/OCP
  ○   The OCP and OVP LEDs apply to whichever channel last updated them.  Pressing either the OVP or OCP button updates both the
        OVP and OCP LEDs with that single button push.
●      An OCP/OVP trip for one channel does not trip the other channel

[1NFR4R3D]

Hi! Sorry for necroposting.

here is the manual, marked up with corrections and warnings about bugs in the user interface and behaviour:
https://ufile.io/drsjx09j

Could you please upload this file to some other website? These folk seem to want $8/month from anyone who wants to access it!