EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown

[PChi]

I believe that another capacitor killer is heat conduction through the PCB trace from the rectifiers and power transistors directly to the capacitor terminals.

[SeanB]

I always change the card out after around 100 erase cycles, never trust that the card will go anywhere close to rated life, especially with a FAT filesystem that can do multiple writes to the FAT per block of data written to the card.  The cards are cheap enough, especially if you do as I do and go for the lower capacity cards, and keep a few on hand. I still have a half dozen 512M cards that I got for $1 each on sale, used for older cameras that only understand simpler formats. I just use 4G or 8G cards in my camera, keep a spare always in the bag.

[rsjsouza]

I understand the camera rant in this video, but it was a bit more than a little over the top.

I sympathize with Dave on this one; the few times I lost an entire morning or afternoon's work due to equipment failure I had the urge to scream my frustration to the world. The difference is that he can do that (as he has a Youtube channel) and I can't (or wouldn't create a Youtube channel just for that...

As others mentioned, I would also suspect the card as well. Years and years of suffering with corrupt data and cheap brands of flash memory cards, nowadays I tend to stick only with SanDisk and Kingston models coming from reputable suppliers (too many fakes around, similarly to the elec cap on the supply). They seem to have better endurance.

[poorchava]

They did a pretty good job on hardware design. Everything seems to be done properly. I actually think those engineers have much harder life than for example those in Agilent or Tek, because they are pretty much limited to industry standard parts. I guess if that was an Agilent you would see at least OP07 or some expensive, high-spec opamps from LT or AD or even some ASIC (nice to have an in-house ASIC fab, right? O0). Agilent/Tek doesn't care, potential customer is prepared to pay a shitload of dollars for the device. I bet it took those Atten guys quite a lot of time to design this, according to "on time, on budget, working... Pick two" rule.

I think that those opamp/dac/msp430 boards may have been actually hand soldered. In such design you typically find a broad range of different component values, and maybe the cheap-ass assembly house had only a very old pick and place equipment with very limited number of feeders. And it's much harder to overheat resistor or cap than opamp or microcontroller. So they probably assembled ICs on pick and place and then got some minimum wage (in chinese meaning) workers to hand solder the rest. That would explain difference in soldering quality between ICs and passives.

MSP430F2013 is a very nice chip. I have used it before for temperature readout and stabilisation. Internal reference is quite good too. On the other hand clocking setup is pain in the ass, as it has like 6 different clock signals for all sorts of power saving schemes.

[ftransform]

you replace a SD card after 100 uses seanB?

damn man. Then again I am the type of person that washes ziplock bags. 
I am using my cards which are like.... years old.

Also, why are they using ultra low power MCU in a linear supply? I find the thought amusing.

[robrenz]

From what I have seen so far,  on paper the ugly Rigol DP832 at $409.00 has this thing beat by a mile even though only 3 amp output.  The user interface is certainly in another world even if it is the sick pink/orange color.

[SeanB]

you replace a SD card after 100 uses seanB?

damn man. Then again I am the type of person that washes ziplock bags. 
I am using my cards which are like.... years old.

I have been burnt by cards that died suddenly. Only one that I have used hundreds of times is a Sony MS in a camera, not going to pay the price for a new one, even though it is an 8M memory stick. I once did an experimnent with a Kingston SD card on my EEEPC, used it as the drive running Ubuntu, including swap partition. Left it running overnight, and did nothing with it, just running in idle. After 2 days looked at screen to see a kernel panic message about being unable to access swap space. Card dead, bad blocks all throughout. New card with Puppy Linux then went in it's place. Now I can use the card slot again, all runs in RAM.

[bitwelder]

What do you think about the placement of the circuitry for Ch3?
To me it seemed almost like an afterthought, they first designed the PSU with two channels, then at last minute the usual manager/marketeer from hell show up and claimed that they must squeeze a third channel in, and so instead of re-design the whole thing they just found the few free cm3 where to fit the additional hardware. 

[ivan747]

From what I have seen so far,  on paper the ugly Rigol DP832 at $409.00 has this thing beat by a mile even though only 3 amp output.  The user interface is certainly in another world even if it is the sick pink/orange color.

What the hell! This looks like one of those awful Sony stereos:





But hey, at least the user interface is actually usable!

[CHexclaim]

What the hell! This looks like one of those awful Sony stereos:

http://www.tequipment.net/ProductImages/rigol/dp832/media/dp832_image_1.jpg

But hey, at least the user interface is actually usable!

WOW! It is a mixture of an old rotary telephone with the Space Shuttle cockpit!

[CHexclaim]

Dave, I feel sorry for the lost files.

IMO the inner design of the PS matches with the product performance; on the other hand, the construction quality matches that of the firmware. A real pity.

Did you see the quality of the soldering of the big components? As horrible as the SMD ones.

Charlie.

[kcozens]

It certainly looked like a fairly decent product. Too bad about the crappy UI. Dave, what other supplies did you consider before buying the ATTEN unit? The nice thing about the Internet is it often gives you the chance to find out about a product and discover any problems it might have (like a bad UI) before you buy it. If there were no reviews pointing out the problems with the unit before you got one, at least the EEVBlog teardown will warn others about the product.

[EEVblog]

It certainly looked like a fairly decent product. Too bad about the crappy UI. Dave, what other supplies did you consider before buying the ATTEN unit?

None really.
I hadn't seen another precision triple output supply for anywhere near that price in Oz. I wanted to see if it was too good to be true.

[moebius326]

Hi -
Would anyone have a schematic or service information for either this unit (Atten PPS3205T-3S) or better - the CSI version (CSIPPS55S)? The channel 1 output on mine has died (possibly the relay) and I'd like to get some information before I dive in. CSI had no information and Atten (3 different offices) never replied.
Thanks in advance.

[SparkyFX]

Did someone upload your video again with your permission?
Someone reuploads a whole bunch of your videos, plus other youtube creators and adds spam...
https://www.youtube.com/channel/UCCWPDYbCdcxxWda0VEFhaQg/videos