Author Topic: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown  (Read 14221 times)

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Offline mariush

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Offline Thor-Arne

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Sorry to hear about the camera trouble.
And thanks a lot for redoing the shoot, much appreciated.  :-+
 

Offline c4757p

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His voice at the beginning talking about metal support rods, especially the words "although it's a hope", have a tone of pure despair.
No longer active here - try the IRC channel if you just can't be without me :)
 

Offline RobB

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Dave, I hope you appreciate the irony in using your Atten hot air smd rework station to fix up some of the dodgy joints in the Atten PS  :-//

Thanks for the perseverance given the camera issues.

Rob
 

Offline mariush

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The quality of the boards is just... horrible.

Yeah, give them credit for actually using connectors and gluing the cables but so ugly surface mount..

The 10000uF capacitors are probably fake, the quality of the text is just bad.
I saw some Aishi capacitors somewhere on the front panel which are low quality in general and the rest of the caps spread on boards are equally no-name  - I doubt they would have paid about 6-10$ a piece for those 10000uF capacitors

Wouldn't it make more sense to turn the two boards 180 degrees and have the heatsinks at the sides of the case, with a lower speed/ more silent fans?

This way each heatsink and fan would have clear path all the way to the front of the case and the board for the 6v output would also be less cooked.

Not to mention the two boards could then be merged in the center and they'd save some money on the boards and some components like linear regulators that could be shared.

I guess it costs too much to stamp another hole in the case and pay for a second fan, or something like that. I don't see any other reason...
« Last Edit: March 19, 2013, 11:21:18 pm by mariush »
 

Offline Psi

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Hard to say what exactly happened with the files but i'm guessing the camera records onto a SDcard or similar.

90% of the time those kind of problems are caused by failings in the fat32 filesystem, it's really prone to damage when not unplugged/unpowered gracefully.
The real kicker is the damage doesn't always show up when it happens, it's not until later on (sometimes months later) when files begin corrupting.
« Last Edit: March 20, 2013, 01:43:07 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline fpliuzzi

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Another interesting video Dave. It looks that the negative lead of the 100uF, 16V capacitor at the 31:32 point in the video is unsoldered (unless it is just a weird black reflection in their shiny solder joint).

Frank

ps Maybe you could dump the video clips from the camera to your PC (if it is near you) at regular intervals so that you wouldn't lose too much footage if the camera gets wacky. I'm always having problems with corrupted thumb drives.
 

Offline LaurenceW

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Dave, not my original quote, but here it is, just the same:

"Technology" is simply stuff that doesn't quite work right, yet. There was a time when wheels were technology, but they've been debugged now.

ATTEN you MUPPETS! You've very nearly got a good product here, but you've screwed up. Fix all the stuff Dave's told you about, and come back and tell us when you have.
If you don't measure, you don't get.
 

Offline LaurenceW

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I would think that the biggest parameter that a fake supply cap would not be able to match to the original would be it's Equivalent Series Resistance (ESR). Dave, if you have the strength, can you measure one or two of those "ChemiCons" <snigger>

To measure a "true" heatsink temp with a non-contact IR device, simply stick a 25mm square piece of black insulating tape on the heatsink, and measure that. Works for me.
If you don't measure, you don't get.
 

Offline David_AVD

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Interesting that the SIL pad for the 5V series pass transistor also has heatsink compound on it.

I was always under the impression that you shouldn't use compound in conjunction with a SIL pad.  All it does is add thickness and impede the thermal transfer.
 

Offline justanothercanuck

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #10 on: March 20, 2013, 12:42:16 am »
Interesting that the SIL pad for the 5V series pass transistor also has heatsink compound on it.

I was always under the impression that you shouldn't use compound in conjunction with a SIL pad.  All it does is add thickness and impede the thermal transfer.

Is the SIL pad even worth using?  Since the transistor is screwed to the heatsink, it's still got the screw to conduct through...?  ???
Maintain your old electronics!  If you don't preserve it, it could be lost forever!
 

Offline poodyp

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #11 on: March 20, 2013, 12:47:01 am »
There're likely bushings on the screw to prevent contact. 
 

Offline IvoS

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #12 on: March 20, 2013, 12:58:10 am »
Yep. Those caps are fake big time.
 

Offline David_AVD

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #13 on: March 20, 2013, 01:15:35 am »
Interesting that the SIL pad for the 5V series pass transistor also has heatsink compound on it.

I was always under the impression that you shouldn't use compound in conjunction with a SIL pad.  All it does is add thickness and impede the thermal transfer.

Is the SIL pad even worth using?  Since the transistor is screwed to the heatsink, it's still got the screw to conduct through...?  ???

The SIL pad provides the insulation for the metal backing of the transistor.  The hole in that particular package is insulated.  Photo of 2 pin version attached.

 

Offline Dave

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #14 on: March 20, 2013, 02:28:16 am »
I was REALLY hoping you would disassemble the bloody thing and remove that damn eyelash from the display. Seeing it irritates me. :scared:
<fellbuendel> it's arduino, you're not supposed to know anything about what you're doing
<fellbuendel> if you knew, you wouldn't be using it
 

Offline amspire

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #15 on: March 20, 2013, 03:16:03 am »
To measure a "true" heatsink temp with a non-contact IR device, simply stick a 25mm square piece of black insulating tape on the heatsink, and measure that. Works for me.
I was thinking the same thing watching the video. Doesn't even have to be black tape - any colour electrician's tape works as well, or even paper-based masking tape. They are all black at the IR frequencies the temp meter works at. Kapton tape is probably better. Even a black waterproof marking pen does a good job.
« Last Edit: March 20, 2013, 03:21:01 am by amspire »
 

Offline Lightages

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #16 on: March 20, 2013, 07:08:19 am »
Thanks for redoing the video so we could see the insides.

My end thought on this is that the engineers wanted to do a god job but after the whole thing went to shit. I will look elsewhere because the user interface is crazy, and the build quality had many issues. Too bad that the whole thing got let down by the idiots building and programming it after the hardware design was done.
 

Offline PChi

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #17 on: March 20, 2013, 11:37:19 am »
Thanks for the Teardown. I think that Atten use two 2SD1047 in parallel for the 30 V 5A supplies because of the Safe Operating Area limitations. The ST Microelectronics data sheet Figure 2 shows 2 A at 50 V for DC. I guess that is with the junction temperature = 25 degrees C. I guess that with the transformer tap switching it should only ever be subjected to those conditions for a few ms so there is some margin for the Safe Operating Area getting smaller at higher junction temperatures.
 

Offline nitro2k01

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #18 on: March 20, 2013, 12:46:30 pm »
Hmm, are those thermostats normally open or normally closed? (Yes, it ought to be normally open with that configuration, but that's why I'm asking...)

If you were trying to get a full load on CH2/3, shouldn't you have used the lowest setting on the CH3 rail to maximize the drop over the transistor? I see you're using the resistor for this though. So maybe even just put it into constant current mode byt shorting it out.
Whoa! How the hell did Dave know that Bob is my uncle? Amazing!
 

Online PA0PBZ

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #19 on: March 20, 2013, 01:04:28 pm »
Hmm, are those thermostats normally open or normally closed? (Yes, it ought to be normally open with that configuration, but that's why I'm asking...)

I was wondering the same, usually these things are NC but that would not make sense in this configuration.
Keyboard error: Press F1 to continue.
 

Offline firewalker

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #20 on: March 20, 2013, 02:27:11 pm »
Searching for "KSD302" shows N.C. and N.O. types.

Alexander.
Become a realist, stay a dreamer.

 

Offline nathancrum

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #21 on: March 20, 2013, 03:21:47 pm »
I understand the camera rant in this video, but it was a bit more than a little over the top.  Also it seems more likely the memory card is to blame than the Canon, but I digress.  Thank you for redoing all the video regardless - it's much appreciated by us fans of the show.
 

Offline c4757p

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #22 on: March 20, 2013, 03:31:37 pm »
I understand the camera rant in this video, but it was a bit more than a little over the top.

Eh, who cares? It was funny, and felt good for anyone who's had something similar happen.
No longer active here - try the IRC channel if you just can't be without me :)
 

Offline Winston

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #23 on: March 20, 2013, 04:07:04 pm »
I was looking forward to you measuring the temperature of that electrolytic cap that's way too close to the heat sink.

TI Power Tip 50: Avoid aluminum electrolytic capacitor pitfalls



 

Offline nathancrum

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Re: EEVblog #440 - Atten PPS3205T-3S Triple Output Power Supply Teardown
« Reply #24 on: March 20, 2013, 05:02:31 pm »
Oh yea - regarding the cap that was "way too close".  Electrically that may still be the case for adequate isolation (I don't know), but thermally speaking - it's at the opening to the (channeled) air flow for the heat sinks.  If anything that should be one of the best cooled capacitors in the case regardless of proximity to the heatsink.  The leading face of that heatsink should also be the lowest temperature point on it and emissivities of both shiny parts are not going to be great so thermal radiation isn't going to be terribly significant.

The massive cap near the side of the heat sink on the other hand may have a nice gap, but it will experience basically zero air flow for cooling.  I would expect that cap to get much warmer than the one in the center of cooling air flow path.
 


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