Fnirsi is one of those brands that seem to pop up more and more often, usually for portable oscilloscopes and kin. Their IPS3608 bench power supply is a bit of a departure from that, offering a mains-powered PSU that can deliver up to 36 VDC and 8 A in a fairly compact, metal enclosure. Recently [Joftec] purchased one of these units in order to review it and ended up finding a few worrying flaws in the process.
One of the claims made on the product page is that it is ‘much more intelligent than traditional power supplies’, which is quite something to start off with. The visual impression of this PSU is that it’s somewhat compromised already, with no earth point on the front next to the positive and negative banana plug points, along with a tilting screen that has trouble staying put. The USB-C and -A ports on the front support USB-PD 3.0 and a range of fast charge protocols
The ‘intelligence’ claim seems to come mostly from the rather extensive user interface, including a graphing function. Where things begin to fall apart is when the unit locks up during load testing presumably due to an overheating event. After hooking up an oscilloscope, the ripple at 1 VDC was determined to be about 200 mV peak-to-peak at 91 kHz. Ripple increased at higher voltages, belying the ’10 mV ultra-low ripple’ claim.
A quick teardown revealed the cause for the most egregious flaw of the unit struggling to maintain even 144 Watt output: a very undersized heatsink on the SMPS board. The retention issues with the tilting issue seemed to be due to a design choice that prevents the screen from rotating without breaking plastic. While this latter issue could be fixed, the buggy firmware and high ripple on the DC output make this €124 ‘285 Watt’ into a hard pass.
200mv = 0.2V. When supplying 1V. That is TWENTY PERCENT RIPPLE.
But-but-but…if you lie under your bench with a mirror to see the top of your bench, with your left arm behind your back, and your right foot behind your head, just look how good the display looks?
Agreed…form over function.
FNIRSI generally greatly overstates their product capabilities. But the real question is, how does it compare to other products in the same price range? My guess is still pretty bad (20% ripple is no joke) and looks like you can get slightly lower specs for a comparable price from a good brand. But it’s good to compare with other products at the price range when you state “don’t buy this”
For example, I have a 1013D scope from them, while their 100Mhz claim is just wrong, it’s only usable for things up to 10Mhz. It is perfect for what I need and better then anything else I could find at that price range. Yes, a Rigol is quite a bit better, but also at least double the price. And depending on what you do, the 1013D could be just good enough.
This might be the case for this power supply as well, but I doubt it…
TBH for a lot of hobbyists this stuff coming from China is “good enough” and at 1/2 to 1/10th of the price – or compared to used gear, 1/2 to 1/5th of the bench-space.
As long as you keep your eyes open and take all the marketing claims with a large dose of salt / 50% de-rating, there are useful tools to be had.
Also – a lot of this stuff does have better features, better usability/interface, open serial ports or BT control etc. where the established players either lock stuff down or charge extra.
I’ve so far managed to avoid the cheap garbag and Fnirsi has always given me that vibe.
there are good reasons why name brand test gear costs more but is worth paying for even when buying second hand
This is one example where you get just a little less than you pay for.
I miss the days when Olson Electronics was around the corner, and a 35W4 was only $1.25.
And diodes were 10 cents but you still needed the tube diode for the heater string.
I do like low cost tools, and accept lower performance from them in a lot of situations, but fnirsi is both lying though their teeth in the datasheets, and attempting to hide serious flaws in their hardware (For example by always turning averaging on in their scope to hide a faulty (overly simplistic?) front end design) that it is not worth buying.
Positive reviews about fnirsi stuff are only maid by paid “reviewers” and beginners who are already happy that the thing sort of works at all. While many other reviewers are report having “difficulties” with the flaws in fnirsi stuff. The whole brand is a sour joke. Please don’t buy it. Save up a bit more money, and then buy something that probably looks a bit less flashy on your desk, but you’ll have something that actually works.
It’s not that hard to make a GOOD bench supply at a low cost. I just don’t understand why the choice seems to be between poorly designed ones at ridiculous prices (OK, tariffs), and good ones at astronomical prices.
I suppose it’s the low volume…still, it’s annoying enough that when I wanted a 5A, 13.8V analog supply for my HF QRP rigs, I built my own.
Ripple at 90kHz really sounds like absolutely zero filtering. A simple R-C filter would wipe that out. Perhaps the unit tested was defective.
Well if the ripple appears as common mode as it does on some isolating DC to DC modules getting rid of the ripple to compare with analog standard power supplies can prove challenging.
I never would have watched this video. All the youtubers figured out to all “Watch This Before YOu Buy” to their titles to get more clicks.
This says “don’t buy” though, with no qualifier.
I typically am ok with low cost Chinese tools, and a lot of them truly do punch above their weight class offering excellent value for dollar. But, every fnirsi product I’ve ever tried has been utter garbage. Scam products that only barely ‘work’ at all, with outright lies on the spec sheets and fire hazards in the product. Power supplies that overshoot by tens of volts for a couple hundred milliseconds on startup and on entering protection, for example. Made in China doesn’t automatically mean ‘crap’ to me, but ‘fnirsi’ does.
I gotta say, I disagree with FNIRSI haters. I ran into FNIRSI when I bought their USB power monitor, because it is computer readable. It works ok, and allows me to monitor low power microcontroller projects.
Since that, I bought few other specialty products: battery meter, spot welder, radiation monitor, moisture meter, and their new compact scope. They are reasonably made, and good value for the money.
The battery meter is a workhorse, it shows the voltage under load and internal resistance, measured by four contacts method. I don’t know anything comparable for less than few thou.
Put a levelled sinewave generator on the FNIRSI scope inputs and wind the frequency up.
You’ll probably find that as the scope reaches its real physical frequency limit, just as the amplitude on the display starts to drop, it will jump back up again as you continue to increase the input frequency.
FNIRSI are playing dirty tricks in software to artificially increase the amplitude of the displayed sinewave to fake a higher bandwidth limit.
This has been verified by decompiling the firmware on some scopes.
I’ve verified this using my Tektronix SG5030 levelled sinewave generator on an FNIRSI 2C23T.
Apparently this is only done with sinewaves, as they are what is most often used to determine the -3dB point.
On the other hand, their HRM-10 Battery Voltage Internal Resistance Tester lined up pretty well with my HP 4338A Milliohm Meter, so there’s that.