Author Topic: Preparing EEZ H24005 for crowdfunding  (Read 55236 times)

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Offline Helix70

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #125 on: May 28, 2017, 06:50:56 am »
The instructions look good to me. Good tip for the USB cable, don't want to break the Arduino!
 

Offline Kean

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #126 on: May 28, 2017, 07:15:37 am »
I agree, the instructions look very clear and thorough.  Well done!
 

Offline opticpow

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #127 on: May 28, 2017, 08:39:46 am »
Given that there is no more of these to be bought, is anyone else interested in getting some made.

I am.
 

Offline Kean

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #128 on: May 28, 2017, 09:00:23 am »
Given that there is no more of these to be bought, is anyone else interested in getting some made.

I'm getting two of the Crowd Supply units, but if they work out as well as expected then I will probably want another one or two.
My lab has expanded  ;D
 

Offline timgiles

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #129 on: May 28, 2017, 09:24:32 am »
Instructions look good.

I could definitely see myself building another early next year, so prehaps we need to look at opening up a online list for those interested that once it hits 50 (?) a larger order can be placed.
 

Offline mrpackethead

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #130 on: May 28, 2017, 10:06:07 am »
Given that there is no more of these to be bought, is anyone else interested in getting some made.

I'm getting two of the Crowd Supply units, but if they work out as well as expected then I will probably want another one or two.
My lab has expanded  ;D

The big challenge is the case.. the rest of it is resonbably straight forward.  I'd really hope prasmix can do somethign, but it appears hes not keen too.
On a quest to find increasingly complicated ways to blink things
 

Online prasimix

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #131 on: May 28, 2017, 09:34:59 pm »
Given that there is no more of these to be bought, is anyone else interested in getting some made.

I'm getting two of the Crowd Supply units, but if they work out as well as expected then I will probably want another one or two.
My lab has expanded  ;D

The big challenge is the case.. the rest of it is resonbably straight forward.  I'd really hope prasmix can do somethign, but it appears hes not keen too.

Hm, I'm not quite understand what I can do on top of what is done: the enclosure is now fine tuned (after few iterations) to house all PCBs and other elements, it also include simple heatsinks, AC/DC module mounting frame and 3.2" TFT display mounting frame. Only what remains that someone contact Varisom and order 20 or more units to get better price. I believe Varisom shouldn't have any complaints if new order comes from someone else (I can forward a contact name and inform Varisom about it). There is no need to repeat (and pay!) a whole process of prototyping. You can possibly even order a new color if existing one (RAL 5022) is not suitable.
 
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Offline mrpackethead

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #132 on: May 30, 2017, 03:05:38 am »
Hm, I'm not quite understand what I can do on top of what is done: the enclosure is now fine tuned (after few iterations) to house all PCBs and other elements, it also include simple heatsinks, AC/DC module mounting frame and 3.2" TFT display mounting frame. Only what remains that someone contact Varisom and order 20 or more units to get better price. I believe Varisom shouldn't have any complaints if new order comes from someone else (I can forward a contact name and inform Varisom about it). There is no need to repeat (and pay!) a whole process of prototyping. You can possibly even order a new color if existing one (RAL 5022) is not suitable.

I was hoping that you might be taking more orders.. so i can just buy a kit.. however happy to order them.  In fact if i need to, i'll make one in my shop.. 
On a quest to find increasingly complicated ways to blink things
 

Online prasimix

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PCB modules are coming...
« Reply #133 on: June 13, 2017, 02:27:41 pm »
I got today confirmation from ITEAD that assembled PCBs will be ready for shipment tomorrow. That means that boards should comes to me next week when I need to perform basic testing, upload firmware v1.0 (it has to be ready to the end of this week) and pack everything and send to Crowd Supply for final delivery to your addresses.
I'm going to add another update on campaign pages when get tracking number from ITEAD.

 
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Offline Dwaine

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #134 on: June 17, 2017, 01:02:26 am »
Looking forward to when my unit arrives.  The firmware looks very well done   I was looking at the GITHub code.  This will put the Rigol and Siglent power supplies to shame.

I think there will have to be another opportunity.  When people see this power supply in action.  The demand will be there. 
 

Online prasimix

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Assembled modules arrived ...
« Reply #135 on: June 25, 2017, 05:05:11 pm »
Assembled modules arrived at Friday as scheduled in boxes that are a little bit funny and doesn't look as something that could efficiently protect its content ...



... but inside is huge amount of bubble wrap to protect modules:



So, first think that I did on Friday is to run a quick test of all three types of boards to see if they are working as first batch of 10. I'm happy to say that it seems that they are behaving as expected. I was a little bit nervous about that since first batch due to small quantity was manually assembled and main production has been done on automated assembly line.

I just finished all AUX power boards. A simple testing of soft-start/stand-by, fan control/speed measurement and DOUT2 relay was performed. I found on many boards that header's pins (positions X4, X8 and X10) are bended (I don't know if that is connected with strange packaging or something else during production) but nothing alarming that cannot be rectified quickly. Another issue was with inductor L5 that drop off from half of dozen boards, but I also fixed that.
All boards are mounted to already prepared rear panels, put in boxes and they are ready for final insertion to main transportation box that was presented in some of recent post:



... another view below right desk:



Tomorrow we are continue with Arduino Shields.
 
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Offline julianhigginson

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #136 on: June 26, 2017, 10:09:04 pm »
woohoo!! getting very close now!
 

Offline Aigor

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #137 on: June 28, 2017, 08:47:14 am »
Start to be impatient to receive my "Christmas gift"  ;D
 

Online prasimix

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Another (very) busy week
« Reply #138 on: June 30, 2017, 10:19:18 pm »
A short update about what was achieved this very busy week. All Arduino Shield boards are tested and I found that percentage of them doesn't work. I don't know what is average figure for faulty assembled boards in the industry, and would like to compare it with what I got here. So if someone have some idea please let me know.
I made some basic testing that also required plugged in Arduino Due board and 3.2" TFT display. Both of them came from the same Hong Kong based dealer found on Alibaba. I got very interesting situation here: first it seems that dozen of 3.2" TFT displays don't works as expected, then I found that their contacts are "greasy" or just corroded but "contact spray" saves my day. Next, I got errors that pointed into direction of faulty Arduino Shield boards (another dozen) that ends up with another completely unexpected surprise: Arduino Due boards with MCU that has faulty analog inputs! That MCUs didn't show any problem with firmware uploading, USB or SPI communication but analog inputs reported always max. value (like logic high level).
Now I can say that selected dealer of cheap components wasn't good choice. The bad thing was that I was completely unaware of such possibility and didn't test throughly all Arduino Due (and displays too!) before, report that and save some time (and money) with replacements.

All Power boards were installed on heatsinks, and so far I tested less then 20% of them performing basic voltage and current programming (with load connected). Percentage of faulty assembled boards is comparable with above mentioned Ardiuno Shield boards and I'll continue with testing the rest of them. Also for tomorrow is planned to start boxing of complete kits just to get some idea about how time consuming that process will be.
 

Offline Rerouter

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #139 on: June 30, 2017, 11:27:52 pm »
in a low complexity assembly run of 400 units I had 6 turn out to be faulty, 2 from a dry joint, 1 from a missing 0603 component, and 3 unknowns, possibly an open trace on the board.
 

Online prasimix

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #140 on: July 02, 2017, 09:52:26 am »
in a low complexity assembly run of 400 units I had 6 turn out to be faulty, 2 from a dry joint, 1 from a missing 0603 component, and 3 unknowns, possibly an open trace on the board.

Thanks for feedback. I assume that your manufacturer didn't perform any testing, but just delivered what came out of production line. I finished this morning testing of all boards. Numbers in my case are very discouraging: 49 pcs of 600 Power boards are faulty (~8.1%) for various reasons: 3 mechanical damage of C3, C15 was 5 times found detached in packaging bags (same with C55 but two times). The rest represents boards that failed to pass simplest testing (i.e. voltage and current programming over the whole range 0-40V and 0-5A).
In case of Arduino Shield boards (300 pcs) 11 are faulty (~3.6%). Now it's question how much time I have to spend to repair faulty boards.

To add more "joy" to the whole story my son broke his arm in unusual way that surgery last almost five hours. He is still in great pain and we have to see what the result will be.
Anyway before got a call from ambulance we managed to put into boxes almost hundred units:

 

Offline Strada916

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #141 on: July 02, 2017, 10:14:06 am »
Sorry to hear about your son.  Hoping for a speedy recovery. Shocking failure rates. Sorry this has happened.

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Offline Rerouter

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #142 on: July 02, 2017, 10:33:22 am »
The supplier we used was itead, for both the boards and assembly, your yields may be relayed to the complexity, mine where 0603 / 0.5mm pitch min, 10/10 spacing, with 57 components, 3 being QFP's, mixed through hole and smd, on a 2 layer board.

The yeild of the arduino boards surprises me a little, see that there isnt an open connection to VDDANA and ADVREF (Pins 73 and 75 on the qfp), as that is the analog supply.

As for your faulty boards, what is the fault symptoms if you dont mind me asking
 
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Offline julianhigginson

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #143 on: July 03, 2017, 03:14:30 am »
oh no... I hope they sort your son's arm out soon. It's so stressful when your kids hurt themselves, and heartbreaking to see them in pain.



Also - that's not a good manufacturing yield.  I'd forgive maybe 2% for a first run, but expect it under that if the design is right and the manufacturer is competent. 

Look at the power boards vs your prototypes, and see if it's a common problem that's stopping the ability to program V and I. 

I'd also hold off shipping, as if it turns out the design is marginal, you might want to have those boards to hand.

Did these guys also build your prototypes? if they did, at least you know they know what all the components are meant to be.
 
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Online prasimix

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #144 on: July 03, 2017, 09:21:02 pm »
The yeild of the arduino boards surprises me a little, see that there isnt an open connection to VDDANA and ADVREF (Pins 73 and 75 on the qfp), as that is the analog supply.

Many thanks for this one! I found that AREF selector 0603 jumper on all problematic boards is not properly soldered (one end is without contact). After resoldering everything starts to works as expected.

As for your faulty boards, what is the fault symptoms if you dont mind me asking

After additional inspection I can say there is a two major reasons for such great failure rate:
  • thermal pad of IC4 is not connected and
  • one of C15 terminals lost connection (it's ripped off or not soldered properly).

First one cause problem with bias power that become about +12V/-0.5V instead of +5/-5V. If that is a case and you turn on channel output voltage will exceed max. value of 40 V and if load is mistakenly connected that can easily damage low current switch and sense resistor (Q13 and R63). Another possible victim could be IC10 (DAC) but I cannot confirm that yet.
Result of the second issue is that output current cannot reach max. value of 5 A. It's in this case less then 3 A.

Please note that IC4 is not the only one with thermal pad. That is also IC1. But, it is connected on "isolated" ground plane while IC4 is connected on main ground plane that is not so easy to heat up. But that should be a default, or not? I don't know if manufacturer should take such parts in account to adjust soldering process (i.e. selection of temperature, speed, solder paste, etc.). Maybe a considerable number of issues with IC15 connection was also caused with inappropriate soldering process for such bulky part?

So far I successfully repaired 20 Power boards and hopefully I'll fix the rest very soon. There is few other issues: one is very strange: positive and negative input pins of X1 (minifit 3-pin connector) was shorted from inside like on picture below (connector was removed):



Other issues are with C15 that are dropped off the PCB completely (again by mechanical force due to faulty handling or due to inadequate soldering process) and C3 that is mechanically damaged (broken terminals).

I didn't have a time to check what's going on with Arduino Shield boards yet.
 

Online prasimix

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #145 on: July 03, 2017, 09:24:13 pm »
Did these guys also build your prototypes? if they did, at least you know they know what all the components are meant to be.

Yes, they did but assembled them manually. I found the same problem with IC4 mentioned above on few prototypes and warned them about it, but it seems that the same soldering process was used.
 

Offline perieanuo

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #146 on: July 03, 2017, 09:34:39 pm »
Did these guys also build your prototypes? if they did, at least you know they know what all the components are meant to be.

Yes, they did but assembled them manually. I found the same problem with IC4 mentioned above on few prototypes and warned them about it, but it seems that the same soldering process was used.
I worked almost 5 years assembling medical precision lasers with step motors with embarqued electronic modules communicating with rs485 standard and some centralised dsp module.I precise medical stuff for radio-therapy security purpose!(location near Paris)
Failure rate of electronic modules made in China was 10-40% .
So every day I was repairing the low-cost sh....t.
Don't take it bad you'll get to that finish line...
Bon courage I really love your project on my first pay I'll buy the kit.
Best regards , Ovidiu


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Offline Helix70

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #147 on: July 04, 2017, 02:04:30 am »
The problem isn't "made in China", it is more likely how well was it specified, and are they following your specifications. Of course, this increases the price, but we get perhaps 1 failure in 500.

We specify the testing, soldering quality, PCB construction, allowable part substitution, cleaning, solder, flux, conformal coating, inspection methods, surface finish etc, etc.
 

Offline Rerouter

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #148 on: July 04, 2017, 02:38:38 am »
If you check your gerbers for IC4, do you find areas defined on the paste later?
 

Offline julianhigginson

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Re: Preparing EEZ H24005 for crowdfunding
« Reply #149 on: July 04, 2017, 04:09:14 am »
aaaah.... C15 is exactly the type of cap I expected it'd be, from what you said.
http://au.mouser.com/ProductDetail/Panasonic/EEE-FK1J101P/?qs=qE6bgDGEOCtwdzPOVG3QkQ%3D%3D

I hate SMT electrolytics.  I never use them if it's at all avoidable. (and these days with bigger and bigger ceramics becoming available, it's getting pretty avoidable)

They have very high thermal mass, high centre of gravity and relatively small solder lands.
Basically, they are a manufacturing defect waiting to happen.

I've seen so many of these parts improperly soldered, still with some of the solder paste in ball form underneath, and not even fully evaporated carrier. All because the person doing the reflow profile didn't consider the amount of heat these things can suck up. (or they had to keep it lower than they'd like to in order to prevent over-stressing other parts)

And even if soldered correctly, one sharp jolt, and *pop* off they come.

At least they are fast and easy to rework if there's a bit of space around them.

 


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