Best Bench PSU / Short Killer? (max. 400 Euro / 450 $) - Page 1
Forum section: electronics / beginners

author: eevblogger88
author_rank: Contributor
timestamp: March 31, 2022, 04:07:26 pm
content: Hello, I want to start repairing devices and I have bought nearly everything I need, except the power supply.---Louis Rossmann recommends this in his shop:CSI 3005PUSB PROGRAMMABLE 0-30V 0-5A 4 DIGIT DISPLAY ADJUSTABLE LINEAR DC REGULATED BENCH POWER SUPPLY (120 Euro)https://www.circuitspecialists.eu/csi-3005p-usb-programmable-0-30v-0-5a-4-digit-display-adjustable-linear-dc-regulated-bench-power-supplyNorthridgeFix recommends this in his shop:Compact 30V 15A Switching power SupplyYihua 3005D(75 Euro on Aliexpress)https://northridgefix.com/product/compact-30v-15a-switching-power-supply-yihua-3005d/And the "common sense" I found is, that "Siglent" is a very good brand for the price, so I found:Siglent SPD3303X-Epower supply (370 Euro excl. VAT)https://eleshop.eu/siglent-spd3303x-e-power-supply.htmlandSiglent SPD1305Xlab power supply (250 Euro excl. VAT)https://eleshop.eu/siglent-spd1305x-power-supply.htmlOne of the main purposes will be to detect short circuits, send voltage to a chip to see via an infrared camera where a heat spot is.On the NorthridgeFix site a "Short Killer" is recommended, because "Unlike a bench power supply which can go into protection mode or get damaged when used to inject voltage on to a short component, this power supply can withstand the short without burning out or breaking down."Short Finder / short killer power supply used to inject voltage to detect short circuithttps://northridgefix.com/product/short-detector-voltage-injector-power-supply/alternative (OOS on Northridgefix:)Shortkiller (65 Euro)https://www.aliexpress.com/item/4001201574700.html---My question is:What should I have?Both, a PSU, a PSU & Shortkiller or a Shortkiller only?I thought Ive seen Louis Rossmann using only a PSU Bench for injecting voltage, this confuses me thinking I don't need a Shortkiller?At the moment my thought is: Buy a Siglent SPD1305X and use it of injecting voltage to find shorts.Is this the best option?Thank you in advance for taking your time!

author: SmokedComponent
author_rank: Regular Contributor
timestamp: March 31, 2022, 06:36:53 pm
content: QuoteOh dear, this one is also know under Velleman LABS3005DN brand.I do not recommend it. At all. It has a *horrible* interface. Every time you push down knob to set voltage/current limit it also advances digit cursor one digit higher (instead of going into set mode only, *then* advancing cursor on subsequent knob pushes). It is really painful to use. It is okay if you don't need to frequently change voltage or only use 3 of its programmable presets and don't need OCP which is hopelessly slow on this one.I'd recommend Korad instead, for same money

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 31, 2022, 07:19:14 pm
content: Any "bench power supply" should indefinitely survive a shorted output, they're designed that way, that's the whole point of the current setting.A good one will even stay within the set parameters at all times with no turn on, off, or load transition induced spikes. The cheap test is to see how hard it is to destroy a cheap red LED, a good supply won't no matter what you do if the current setting is at 20mA or less and you only connect the LED forward biased.

author: TomWinTejas
author_rank: Regular Contributor
timestamp: March 31, 2022, 08:03:05 pm
content: Quote from: BrokenYugo on March 31, 2022, 07:19:14 pmI believe the intention is to continue to provide power despite there being a short, at a high amperage, in order to identify the failed component using thermal methods (imaging, evaporation, touch, etc).

author: kripton2035
author_rank: Super Contributor
timestamp: March 31, 2022, 08:09:16 pm
content: nice "fail" picture on an aliexpress shortkiller product ...https://www.aliexpress.com/item/1005002612594903.html

author: kripton2035
author_rank: Super Contributor
timestamp: March 31, 2022, 08:10:48 pm
content: Quoteyou could also try the cheap shorty-with-display to find short circuits on a board...http://kripton2035.free.fr/Projects/shorty-display.html

author: eevblogger88
author_rank: Contributor
timestamp: April 01, 2022, 04:06:00 am
content: Quote from: SmokedComponent on March 31, 2022, 06:36:53 pmWhich Konrad exactly?Quote from: TomWinTejas on March 31, 2022, 08:03:05 pmThat's right

author: geneonline
author_rank: Contributor
timestamp: April 01, 2022, 10:24:02 am
content: There is a few konrad dc power supplies to choose from. Since you are only looking for shorts, go with the 80$ dollar one .KORAD KD3005D - Precision Variable Adjustable 30V, 5A DC Linear Power Supply Digital Regulated Lab Gradehttps://www.amazon.com/dp/B00FPU6G4E/ref=cm_sw_r_apan_i_VMC4V328S1J9Z4CPY1YSunless you may want program availability later in use for about 139KORAD KA3005P - Programmable Precision Variable Adjustable 30V, 5A DC Linear Power Supply Digital Regulated Lab Gradehttps://www.amazon.com/dp/B0085QLNFM/ref=cm_sw_r_apan_i_N2SKD8WFZR6BJV3EVQBWCant go wrong with either. But I would pick the cheaper for what you are doing with it.

author: geneonline
author_rank: Contributor
timestamp: April 01, 2022, 10:28:04 am
content: There is a lot of tear downs of both models and the construction and durability is excellent for the price point. Just search the model numbers and check out some YouTube videos. They have improved a lot since the first ones came out that would burn up quickly. Look for more recent to get a better guage of them now

author: eevblogger88
author_rank: Contributor
timestamp: April 16, 2022, 12:11:42 am
content: I saw that Northridgefix from Youtube seems to have a the same / a extreme similar bench power supply to this one:https://eleshop.eu/rigol-dp832a-labvoeding.htmlIs Rigol a good company?Its the DP832 Bench Power Supply.

author: Electro Fan
author_rank: Super Contributor
timestamp: April 16, 2022, 02:24:14 am
content: There are several Korad models to consider including 3 with similar model numbers.KORAD KD3005D - probably not what you want (limited user interface)KORAD KA3005D - probably what you want (excellent value)KORAD KA3005P - same as above but offers computer control if needed/wanted

author: eevblogger88
author_rank: Contributor
timestamp: April 16, 2022, 02:29:26 am
content: Quote from: Electro Fan on April 16, 2022, 02:24:14 amThank you, I just saw this video:Will choose the KA3005P now, because I plan to show the current & voltage on video recording, which I hope can be read by a pc

author: ebastler
author_rank: Super Contributor
timestamp: April 17, 2022, 07:59:47 am
content: Quote from: TomWinTejas on March 31, 2022, 08:03:05 pmYes, that's what all lab bench power supplies do. You can use them as a constant current source, so of course they need to continue to supply current when the current limiter is active.Many bench suppliesalsooffer a mode where they shut off when the current limit is exceeded. This is meant for use cases where the high current indicates a failure mode and one wants to protect the connected load from potential damage. But that is always an optional mode, selectable by a front panel control, in my experience.The Korad KA3005P which the OP is now gravitating towards does support both modes, btw.

author: wizard69
author_rank: Super Contributor
timestamp: April 24, 2022, 12:11:00 pm
content: QuoteWell if you are just starting out and you have this question, I would suggest that you need to get experience. This can lead to making better decisions about equipment.As for power supplies, these are not tools to obsesses over. A good bench supply is very useful but what is the "best" is often comes down to personal preference. I might suggest B&K Precision for example. In the end it comes down to the capabilities you need.

author: cdev
author_rank: Super Contributor
timestamp: April 24, 2022, 01:01:15 pm
content: There is no "best" power supply for such a general feature. I have two bench supplies that have adjustable current limiting. Virtuallly all bench supplies that can do adjustable current limiting work okay for this. See if you can try it out.I got two pretty good deals on mine. The first one I bought broken and fixed it.A Sorensen XP series (its an old boat anchor) triple bench supply. It might coast as must as $400 new.. But I got it for $60 in a nonfunctional state and replaced the digital display chip of one of the three supplies. That was an easy fix in retrospect. Now it works perfectly.and a GW GPC-3020. dual tracking bench supply. Which cost me $70. From the big ITT college sale..Both are good for preventing thermal runaway with shorts. Both work fine for this, allowing setting a current limit.Both visibly change and click when they switch on the current limit function. Thats the feature you may need.Thats the feature that makes a decent bench supply a good bench supply.If you're designing hardware, you really should have this feature. It will save your expensive new parts.The main difference between the two is the granularity of the current adjustment. The Sorensen triple supply gives me the very specific ability to set the current limit in significantly more detail as to when it will trip. Its accurate to 1 ma.. much more detail, it has a very fine adjustment, which uses a triple vernier adjustment, which can be very closely adjusted. The other supply still lets me adjust the current limit fairly close, too. (It uses a one turn log pot. Which is enough for it to be very useful) So they both are pretty decent as bench supplies go.This in practical terms lets me set the limit at just a few MA more than the power required for normal operation.Say if I want 50 ma, I can have the supply trip the current limit at 53 ma.They both actually do a pretty decent job of this. I dont want to give the impression that the GPC-3020 isnt adequate. It is. Its fine and it works great. On both of them, its easy to see when the current limit kicks in, too.When the power draw goes a bit higher, it clicks into the limit mode. It then makes an audible sound. This is useful if you're a room or two away so you can come back to see whats happening. Both make fine supplies for this. Its the ability to trip into current limit mode that saves your hardware.Thats the main requirement with a bench power supply, this feature. It doesn't need to be super fancy, just needs to work. And be visible+audible.I like the click for indication. The power supply then provides the current limited amount of power, no more. It is vastly overbuilt so it does it and could do it continuously. Even into a short circuit. (With a red light)Nice.

author: Fraser
author_rank: Super Contributor
timestamp: May 11, 2022, 12:18:45 pm
content: The topic of these “Short Killers” caught my eye after NorthridgeFIX used such a unit to stimulate a shorted PCB track whilst monitoring the PCB with a thermal camera. After some research into such “Short Killers” I was pretty much horrified at the intended use !When a PCB has a shorted power rail, I can fully understand injecting current into the rail and checking what gets warm, or hot, beyond the copper track itself. In many cases a thermal camera will lead you to the point where the short is located or the heating of the copper track finishes. To achieve such current injection you need a low voltage regulated power supply capable of delivering a few Amperes of current whilst connected to close to Zero Ohms.. Many lab power supplies will do this but you need to check their “short circuit” behaviour as some might well go into protection mode if a short is present. Most I have used just current limit to the user selected value though. On some power supplies you actually short the output to set the current limit before use. With a lab power supply you can set a sensible voltage and current limit. The cheaper “Short Killers” are pretty scary as they have only a setting for output voltage and no limit on the current beyond their maximum capability, which can be 20A or 30A in many casesThis is why they are called “Short Killers”….. they are designed to inject a “safe” voltage to prevent over-voltage damage, but they then feed high current into the shorted PCB rail to burn away the shortThis is well outside any accepted short tracing process that I have ever been taught. Causing mild heating by current injection is sensible…. Trying to burn out the short is just asking for trouble. If a short is on a thin PCB track and you go injecting 30A, you are playing Russian Roulette with whether the shorted component burns away before the copper track overheats and distorts, or worse still, melts. Remember that the power plane is often within the PCB layers so if a thin power track gets damaged, you are in a worse situation that when you startedI consider “Short Killing” a brute force attempt at repair that is more suited to a “back street” dodgy repair establishment. Decent thermal cameras are now very affordable so such brute force approaches appear crude. If you look on YouTube, you will see a lot of videos showing “Short Killers” being used by repair shops that clearly are not concerned about incinerating a customers PCB !The good news is that there are now versions of the Short Killer that are more like a high current bench power supply. These offer both voltage and current control to the user. A voltage of less than the shorted rails nominal voltage is set and the current limited to something sensible for thermal PCB analysis using a thermal camera, IPA or flux dusting. I personally use thermal imaging and 2A is often more than enough current to trace a shorted component. 2A is less likely to cause PCB damage than the crazy uncontrolled 30A provided by some Short Killers. Sadly the better Short Killers are actually just as expensive as a half decent lab power supply. They have the advantage of being able to deliver a “burning” current in the 10’s of Amperes, but then, as I have just stated, I would not wish to inject very high currents into a modern multi layer PCB.My advice…. Stick with a low voltage lab power supply with a spec of 30V @ 3A or 5A. That will cover most scenarios for you. Go for a 5A rated supply if you can as 3A can be a bit low for some situations. No need for 30A unless you intend to charge some high capacity batteries !Fraser