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| Inside the new Korad KA3305P linear PSU |
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| Scottjd:
--- Quote from: kelchm on January 16, 2018, 06:04:02 pm ---Can anyone share the dimensions of the KA3305P? It looks like the dimensions listed by SRA are incorrect. --- End quote --- Measurement are just a tad bigger rounded off the actural size. They include the feet, knobs, screw heads, handle on top, and front posts. In my video, o don’t think I measured or considered the feet, or the handle on top. Mine is a KA3305P, I don’t think the extra programming USB plug port makes a difference in this size. They all go into the same case, just an added whole for the USB and additional PCB board plugged into the unit inside the case. Don’t forget to consider how far the plug sticks out the back when it’s plugged in, you can always buy a right angle plug also so it doesn’t stick out as far off a shelve. I’m thinking this is what your looking for to make sure it will fit in the space you want it? Scott |
| Scottjd:
--- Quote from: rsfoto on November 10, 2017, 01:59:53 pm --- What I found out is that if I have channel 1 voltage at 0.00 I can nor adjust channel 2 in any way. Getting the adjustment up to 0.01V in CH1 then I can adjust CH2 :-) I know it is nonsense not to have something adjusted but it happened by pure curiosity that I found it out. Same happens with the current adjustment. regards Rainer --- End quote --- Thinking back, I believe this is one of the bugs I reported to Korad. The other gotcha I noticed on older manufactured units, is if you have the power enabled, turn off the unit, then turn it back on it will still have the power enabled. UPDATE: Its been a while using this one since I own 3 different 3 channel PSU’s. But I just remembered on this newer model it wasn’t a bug. Channel 2 is the master by design. So if channel 2 it turned off all the way it cuts any power going to channel 1. I know this is sort of backwards, I would of rather they made channel 1mthe mater, but they didn’t. Still I have 2 of these, the one older 3 channel and they are all still running as expected. Note: I did have a fan go out on my older unit, well it didn’t stop all the way, just made some weird bearing noise sometimes when I turned it on. So I want to mention if you ever replace this fan on the older 3 channel units, it’s a 24V fan, not a 12V fan like a regular common computer fan. So watch out for this, I thought the bug you mentioned was corrected the same time that the power staying on was corrected. It’s possable you might have bought old stock, or a refurbished old unit they sold to you? The opinion on the power bug is mixed. Some people like this and consider it a feature because if the main power goes out when taking long time lapsed measurements on a project, then the unit continues to put power out to,the DUT when the mains power is restored. This only works of the logger is battery operated. I don’t know if a mains powered logger would continue taking measurements if the mains went out, this would depend on the logger unit and it features. I reported this because I considered this a potential danger since the unit is capable of putting out 62VDC and 5 Amps, or 32VDC and 10 Amps, or 32VDC and 5 Amps depending if its running in serial or parallel mode, or how you have it wired at the time. You might want to test this. Unfortunately it does not have the ability to update firmware, but was fixed and corrected with a firmware. You can contact Korad or your local supplier, sometimes they might be willing to just send a replacement board with the new firmware loaded on the chip. Its cheaper then shipping to them, but only request this, or attempt to replace the board if you feel comfortable wit something like this. It has a lot of capacitors and stored power that can be lethal or give you the shock of your life. Scott |
| Candid:
--- Quote from: SantaClaw on December 18, 2015, 06:49:52 am --- --- Quote from: torch on December 18, 2015, 01:50:50 am --- --- Quote from: SantaClaw on December 17, 2015, 03:47:23 pm ---Also, the most noisy thing is the regulators for the fan, they keep buzzing, changing with the pitch of the fan... --- End quote --- Mine don't buzz. Maybe yours has a bit of a gap between a heat sink and the board? --- End quote --- Well, they/it will start making a buzzing/grinding sound about 45 to 60 seconds after I turn it on, with no load. I had the cover off, and it looks like it applies very low power to the fan at this stage, PWM? it doesn't spin on it's own, but starts if I give it a little help. The fan spins easily though, so it's working as it should, also it starts on it's own if I leave it alone long enough. --- End quote --- I got one of this PSUs from Welectron who stated to me that the units they sell are form latest 2018 charge. It does not have the M4 bug others I did not check up to now. What I realized was that I hear a noise from the fan that did make me think that it is defect especially in low power. I checked it with direct voltage and the fan is ok. Then I checked the voltage the fan gets from the psu. Can someone check this with his unit? It is controlled with PWM. My fan runs all the time even without channels on. This "rippel" on the voltage is producing a little annoying sound. When the fan runs faster you can not really hear the ripple but when slow running it is a little disturbing and I wonder how long the fan will run with this special voltage it gets. |
| spidola:
--- Quote from: Candid on August 17, 2018, 11:26:10 pm ---This "rippel" on the voltage is producing a little annoying sound. When the fan runs faster you can not really hear the ripple but when slow running it is a little disturbing and I wonder how long the fan will run with this special voltage it gets. --- End quote --- What if you connect a capacitor in parallel to the fan's power pins? ;) |
| Candid:
That was my first thought and I think I will test it shortly. |
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