Production Testing


14 posts
by rmm200 » Thu May 03, 2012 3:39 pm
With the imminent (well end of June) arrival of my Pi, I am starting to think about what I will receive.

We know the factory sent part of the first build to the Foundation for design checkout.

What testing is done for each board by the factory? What can they afford to do on a board this cheap?

Is power applied?

Does a cousin of the parts picker machine check the test points?

Is the board burned in for 24 hours? One hour? 5 minutes?

Is a monitor attached to check for HDMI output?

Is a diagnostic SD card used to verify function?

What failure rate do they see?

Or does the board go straight from the solder bath to the shipping bag?

Would still love a video of the production line...

Once Farell and RS receive the boards (maybe by their rep at the factory), is each one checked?

Is one in 100 checked?

Do they do any additional testing?

What failure rate do they see?

Back in the day of building disk drives, I remember the racks and racks where every disk drive was burned in for 24 hours. There was a fair bit of failures during this window.
Posts: 259
Joined: Sat Mar 03, 2012 10:25 pm
by nick.mccloud » Thu May 03, 2012 4:13 pm
There have been pictures of inside the factory of them checking boards but I wouldn't get yourself setup for a detailed response and some realism about further checks in 1st world countries should be entertained - the cost would be too prohibitive at this price point.

Context, as ever, is important - what specifically are your concerns - I trust you aren't hoping to build space rockets with Pi's as controllers!
User avatar
Posts: 797
Joined: Sat Feb 04, 2012 4:18 pm
by Max » Thu May 03, 2012 4:24 pm
by rmm200 » Thu May 03, 2012 4:28 pm
Well I can't be the only one curious about the manufacturing process. We have seen the hoards of folks testing the IPads, which have a much better profit margin. So the question comes down to how much testing can be done on a device this inexpensive without affecting the price. I could certainly see automated testing after soldering was complete - apply power and see if test points are within margin. See if smoke comes out...

What I am really hoping for is a statement from someone who knows...

It is for setting expectations too - when my unit misbehaves is it because it had no testing, and a small solder bridge, or is it my 100MA generic power supply...

Curiosity is a terrible thing...
Posts: 259
Joined: Sat Mar 03, 2012 10:25 pm
by nick.mccloud » Thu May 03, 2012 4:40 pm
They are tested in the factory, as per the picture above.

Some that don't work will escape in to the wild but as someone who directs the build of 100's of small microprocessor modules every month I can tell you that  mostly they either pass the test or not, and if they pass a small number, a very small number, have a really odd issue that no other tests would of detected. C'est la vie.

I got mine today. No joy with ethernet or keyboard at first and I could see lots of messages in the boot log about being unable to reset the USB bus. For a few moments I thought I might have a duff one. But I tried various combos of USB devices, unplugged ethernet, changed the powersupply and so forth until I discovered that it was the cheap lead from the power to the Pi that was causing problems.

Many other people have reported similar experiences - thought it was all doom & gloom but turned out to be a peripheral issue.

So, message to the world, Pi's are tested and if you have problems, check things out methodically, it's more likely to be what you've plugged in rather than a faulty Pi.
User avatar
Posts: 797
Joined: Sat Feb 04, 2012 4:18 pm
by rmm200 » Thu May 03, 2012 4:52 pm
OK, based on the picture (I see how I missed it), each board is tested by a technician. In the numbers we are talking about, I was hoping that part was automated. They must have a lot of technicians...
Posts: 259
Joined: Sat Mar 03, 2012 10:25 pm
by dom » Thu May 03, 2012 4:55 pm
I believe every board is plugged into mouse/keyboard/network/composite/hdmi/audio. A test sdcard is booted which displays a composite test image and plays an (analogue) sound (from GPU). It then switches to HDMI, a busybox linux is booted which checks for network, mouse and keyboard, and prints PASSED.
Raspberry Pi Engineer
Raspberry Pi Engineer
Posts: 3864
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge
by jamesh » Thu May 03, 2012 4:55 pm
No testing is perfect. I know of one board so far that appears to have a fault, but I don't think we've had it back yet for testing to see what the problem is.
Raspberry Pi Engineer
Raspberry Pi Engineer
Posts: 10587
Joined: Sat Jul 30, 2011 7:41 pm
by rmm200 » Thu May 03, 2012 4:57 pm
dom said:


I believe every board is plugged into mouse/keyboard/network/composite/hdmi/audio. A test sdcard is booted which displays a composite test image and plays an (analogue) sound (from GPU). It then switches to HDMI, a busybox linux is booted which checks for network, mouse and keyboard, and prints PASSED.



Dom are you serious, or is this sarcastic? (Hard to tell without smileys)

This is exactly the kind of information I was hoping for.

I will accept it as true, and say Thanks!
Posts: 259
Joined: Sat Mar 03, 2012 10:25 pm
by rmm200 » Thu May 03, 2012 7:31 pm
Based on the information so far, this is how I think the testing process works:

(Please let this be a Link..)

Posts: 259
Joined: Sat Mar 03, 2012 10:25 pm
by jamesh » Thu May 03, 2012 7:48 pm
rmm200 said:


dom said:


I believe every board is plugged into mouse/keyboard/network/composite/hdmi/audio. A test sdcard is booted which displays a composite test image and plays an (analogue) sound (from GPU). It then switches to HDMI, a busybox linux is booted which checks for network, mouse and keyboard, and prints PASSED.


Dom are you serious, or is this sarcastic? (Hard to tell without smileys)

This is exactly the kind of information I was hoping for.

I will accept it as true, and say Thanks!


Since Dom is indeed a font of all knowledge Pi, I would believe him.
Raspberry Pi Engineer
Raspberry Pi Engineer
Posts: 10587
Joined: Sat Jul 30, 2011 7:41 pm
by jbeale » Thu May 03, 2012 8:55 pm
dom said:


I believe every board is plugged into mouse/keyboard/network/composite/hdmi/audio. A test sdcard is booted which displays a composite test image and plays an (analogue) sound (from GPU). It then switches to HDMI, a busybox linux is booted which checks for network, mouse and keyboard, and prints PASSED.



That's more testing than I had assumed; doing that amount of connector plug & unplug for a large production run must take some time.  Although I guess manual unsolder & resolder of faulty ethernet sockets would be time consuming as well.
User avatar
Posts: 1886
Joined: Tue Nov 22, 2011 11:51 pm
by scep » Thu May 03, 2012 9:28 pm
rmm200 said:


With the imminent (well end of June) arrival of my Pi, I am starting to think about what I will receive.

We know the factory sent part of the first build to the Foundation for design checkout.

What testing is done for each board by the factory? What can they afford to do on a board this cheap?


They tested every single one like Dom says. Except for yours – as it went past the guy on the line sneezed and missed it. Watch out for the Pink Screen of Death and bogeys in the HDMI port :)
User avatar
Posts: 1063
Joined: Sun Nov 20, 2011 8:53 am
by jacklang » Thu May 03, 2012 9:56 pm
Dom is correct, but for volume production there is a move to bed of nails testing as its faster and less wear on the test leads
Posts: 166
Joined: Thu Aug 04, 2011 10:59 am