Intermittant/permanent display problem with bGeigie Nano V1.1r5a #3106

[Dan Bobczynski]

After assembling the bGeigie kit on 9/9/2018 the basic power on tests worked properly.  The display worked correctly at first then became intermitent. One time while handeling the board with power on, I noticed the FIO LED flicker, then it rebooted and the splash screen came up.  After that, the unit worked correctly and I was able to take several mobile measurement sets and upload them to api.safecast.org (see 31060909.log). 

The display is apparently not affecting the rest of the operation.  I am still able to see and log good data using bluetooth/phone.

The display failure has become constant - it never lights up at all.  So I replaced it with a new one from KitHub with the same results.  

The failure remains after resoldering all FIO pins and display header pins.

There seems to be good signals going to the display.  I see chip select changing, trigger signal, supply voltage, and data signal (see attachment).  But since I don't know what they should be exactly, I need some guidance.

If anyone has had a similar display problem, or has knowledge of how to troubleshoot it, please let me know.

Dan

[-=BDilley=-]

This maybe a silly question.  Do you have a build up of flux or solder whispers that may jump pins especially when the board is tilted in curtain directions or when shook?  I've seen similar oddities as a result in my experiences.

[Dan Bobczynski]

Thanks for the reply.

Its possible.  I have disassembled the unit so I can look at the board and have scrutinized it with high power glasses, and so far found a few solder balls, but nothing causing a short.  I’m continuing to look.

Do you know of anyone who knows what ‘scope traces to expect on the various device headers especially the display?

[Rob Oudendijk]

Did you remove the black plastic that site between the PCB and the header?
Can you send some pictures of the why the SSD1306 is connected to the board?
Or any details pictures of the display?

regards
rob

[Dan Bobczynski]

Yes, I removed the plastic. The display appears to work well.   I tested the display by itself using the adafruit tutorial.  See tutorial photo below.   Here are some shots of the display that came with the kit:

 Adafruit tutorial photo of display test with display supplied with the kit:

Dan

[Jam]

The display seems to have a lot of flex when it's mounted to the main bGeigie board. Probably the pins are too long. There are a couple solutions. The easiest is to just cut the pins shorter. Or, you could put washers or extra nuts on the stand offs to make them longer. I think KitHub puts in a pair of spare M2 nuts for that.

[Dan Bobczynski]

Yes, I noticed the flexing.  I don't like cutting the pins as it would cause extra wear on the female header.  Please see my reply to the recent post by Azby Brown, Nano Assembly Manual Update.