Preparing EEZ H24005 for crowdfunding

[krho]

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?

I've seen this happen to one of Slovenian manufacturers. There was one area on the board that had a large amount of ground on the both sides. Some large components were not soldered properly and sometimes even the IC with thermal pad didn't have a contact. They fucked up 15 prototypes out of 100. And they knew it, they promised to fix it. We then went into the production with them. Out of 1000 200 were having the same problem.
We switched the manufacturer for later batch, we said you are to expect the problem in that area please be careful. We used 500 out of 1000 and all of them were ok.

[perieanuo]

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.

Totaly agree.but you know,longer the list higher the price.just saying cheap and quality is just a dream


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[mrpackethead]

THis is what drove me to manufacturing in house.

[julianhigginson]

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.

That's a bit of a jump to make...

Actually, it sounds like the reflow profile was inappropriate for thermal aspects of the design...
you don't specify that either.
And if you did, I doubt you'd have the capability to confirm it in an overseas contract manufacturer's process anyway. :-)

[alm]

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)

Assuming you use LDOs which are stable with ceramic output caps (no minimum ESR requirement), which excludes some of the cheapest LDOs.

[Helix70]

It has been a long time since I saw a modern smt reg not stable with ceramics, but if that's an issue, add a resistor in series with the cap. Cheaper than the repairs.

[mrpackethead]

And increasingly we are using more and more smps for everything and we want low esr

[prasimix]

Despite the recent stressful situation, I manage to repair enough faulty boards needed for campaign fulfillment. Sorting and packaging was finished yesterday. Everything is ready for pick up that is scheduled for next Wednesday (July, 12th) for shipping by air to Crowd Supply.

[Kean]

Great work!

[Strada916]

Great work there prasimix

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[AlanS]

Good work Prasimix - especially for keeping at it!

[prasimix]

Instead of scheduled pick up last Wednesday, chosen courier/forwarder decided for undisclosed reason to gave up! They told me that in last moment (on Wednesday) despite the fact that we were in constant communication for more then a month. So, they are hopefully the last one who made their contribution to delaying campaign fulfillment. 
Picture of packages last seen in my garage:



Today I received pictures from new courier (DHL via Lufthansa Cargo):



Shipment is scheduled to arrive at Crowd Supply's premise at July, 24th. I'd like to thank once again to all backers for support and patience. We tried to do our best in given condition and wants to apologize in advance if for any reason your kit does not include what is advertised (or not met your expectations in any way).

[mrpackethead]

any spares left over.

[prasimix]

any spares left over.

Yes, something left over, I'm going to make an inventory list of fully usable as of faulty parts that could be of interest.

[Aigor]

Hy Prax, today Crowd Supply sent me a e-mail in which they tell me that i will receive my gift on 16 August

[prasimix]

Hy Prax, today Crowd Supply sent me a e-mail in which they tell me that i will receive my gift on 16 August

Good to know, you're now in their hands 

[grimmjaw]

Hy Prax,

What type of software do you use for the block diagram drawing .Looks good

[prasimix]

The same one that is used for schematic and PCB layouting: Eagle. The source file can be found here.

[garnix]

Shipping date is nearing, great :-)

Just to have everything at hand when it arrives - I read about the need to self-calibrate it. So my (sorry if stupid) question: Do I need anything special to do this calibration?

• Voltage is no problem, I just attach my multimeter to it, I assume.
• To calibrate current, I need some resistor/load - and here my question: How much power is it suppose to dissipate? At what voltage levels is the calibration routine running? So my ordinary - at hand 1/2 W - resistors probably won’t cut it - perhaps I can run many of them in parallel, but that will probably only work practicable if power dissipation is less than 10 W or so...

[prasimix]

Set voltage for current calibration is half of the scale i.e. 20 V (default that can be changed in firmware before compilation).
I'm usually using power resistor of 1R or 3R3. Following the Ohm law, the first one has to be rated to min 25W, another one to 82.5 W. Both of them are mounted on heatsink.

[Aigor]

Hi Prax, do the kit have already compiled firmware flashed?

[prasimix]

Yes, but version 1.0 is used that was available in that moment. I'd like to recommend upgrade to the recent one: 1.01.

[Aigor]

Will be first thing after assembly
Thanks

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[Helix70]

Are you still considering releasing the GUI designer as open source?

[prasimix]

Of course, we are currently shaping it to be usable for others, but need more time than we expected.