part#4311 (so#894508)

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junliu
 
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part#4311 (so#894508)

Post by junliu »

Hi Tech,
part#4311
3 pcs from PO:029-10267 ( 2 pcs OK; 1 pc NG )
7 pcs from PO: 029-10744 ( 5 pcs OK; 2 pcs NG)

Our customer used above parts and met issue as below:
After the USB is plugged in and powered on, 7 pcs are displayed, and 3 pcs are not. Only the background black light, no picture is displayed.
The customer send us video for comparison via email, but I can't upload due to size limit (video size is 21MB).
They want supplier to analysis the reason.
Could you help check and advise?
Thanks.
Jun Liu

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adafruit_support_carter
 
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Re: part#4311 (so#894508)

Post by adafruit_support_carter »

We need to see a photo of the customer's setup showing how they are connecting and using the TFT breakout.

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junliu
 
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Re: part#4311 (so#894508)

Post by junliu »

Hi Tech,
Please see attached comparison pictures for NG part and OK part.
If you want to see more details, I can send you video via email.
Hope it helps.
Thanks.
comparison picture (so 894508).docx
comparison pictures
(121.59 KiB) Downloaded 2 times

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Re: part#4311 (so#894508)

Post by adafruit_support_carter »

Thanks. We need a better photo that shows the quality of the soldering done on the header pins for the NG part:
solder.png
solder.png (262.1 KiB) Viewed 122 times

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junliu
 
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Re: part#4311 (so#894508)

Post by junliu »

Hi Tech,
Please see attached images for details.
Hope it helps.
Thanks.
Attachments
image-1 (so 894508).JPG
image-1 (so 894508).JPG (99.57 KiB) Viewed 116 times
image-2 (so 894508).JPG
image-2 (so 894508).JPG (115.73 KiB) Viewed 116 times
image-3 (so 894508).JPG
image-3 (so 894508).JPG (115.83 KiB) Viewed 116 times

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Re: part#4311 (so#894508)

Post by adafruit_support_carter »

Thanks. The soldering on the headers pins in probably OK. Looks like some of the pads are maybe showing? Which is a potential concern. But probably enough coverage in general to be OK. For now, don't worry about the soldering.

Why is there a double stack of headers underneath the TFT?
tft.png
tft.png (300.35 KiB) Viewed 114 times

That could be another potential source for connection issues.

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junliu
 
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Re: part#4311 (so#894508)

Post by junliu »

Hi Tech,
Please see below customer's reply:
“Why is there a double stack of headers underneath the TFT?”

--->This is because the pin header was cut too short when it was installed on the PCB. After finding the defect, a double pin header was soldered for the convenience of testing.
This has nothing to do with the failure, because the failure has already occurred when the pin header is not soldered.

Thanks.

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Re: part#4311 (so#894508)

Post by adafruit_support_carter »

This has nothing to do with the failure, because the failure has already occurred when the pin header is not soldered.
This is confusing. It sounds like it was known to be not working, but then additional headers were soldered on anyway? If it was showing signs of not working before adding additional headers, why add them? Should trouble shoot first.

Is that double stack of headers added to all TFTs?

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junliu
 
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Re: part#4311 (so#894508)

Post by junliu »

Hi Tech,
Per customer:
The reason for adding soldering headers is: in order to insert the headers into the test jack, test according to the test method on the official website, and we can provide related test videos.

Since not all quantities are bad, the customer thought it's not a matter of misuse.
The customer request for FA, could you help check and advise?
Thanks.

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junliu
 
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Re: part#4311 (so#894508)

Post by junliu »

Hi Tech,
Just got feedback from customer's production line that they found the failure reason is the soldering quality for the wire position is relatively poor.
Considering to their following mass production, they still need supplier's FA, could you help check and advise?
Thanks.

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Re: part#4311 (so#894508)

Post by adafruit2 »

FA for us means First Article inspection, what do you mean?

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junliu
 
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Re: part#4311 (so#894508)

Post by junliu »

Hi Tech,
FA means failure analysis.
The customer wants to send some sample for supplier's analysis, can it be accepted?
Thanks.

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Re: part#4311 (so#894508)

Post by adafruit2 »

we perform failure analysis in the forums so we can get information and photos. it sounds like there was a soldering issue - but unclear from your notes where the soldering failure occurred - if its on their side, it wouldn't help for us to do any analysis!

we'd need more details from the installer to do analysis of what went wrong "soldering quality for the wire position is relatively poor" is not descriptive enough, a photo would be more useful.

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junliu
 
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Re: part#4311 (so#894508)

Post by junliu »

Hi Tech,
We are just advised that previous comment about soldering quality is just customer's suspicion, they still need supplier to analysis why no picture is displayed on the screen.
Under same application surrounding, some works and some doesn't, that means something wrong on the part.
The case has been discussed over 2 weeks, the customer said they had provided all information they can and asked if they can send some defective sample for supplier's check? That will speed up.
We also can send you related testing video via email if you need it.
Could you help check and advise if any better solution to solve the issue?
Thanks.

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Re: part#4311 (so#894508)

Post by adafruit2 »

hi, we are replying within 24 hours to your posts, it would be faster if the customer posted here instead of going through you.

returning the product would not help and we would not do any analysis here because it is within a system we do not control or code or consult for. we do test each board before shipping so if we receive it and the TFT works, nothing is learned. we do not believe it is a screen failure - it is very likely to be an edge-case in programming: perhaps they are driving the display too fast or not waiting for reset long enough. the displays have some slight variation in how they respond to speeds/delays which explains why some work and some do not - particularly since so many are failing. they can run our test example code on arduino UNO following our guide to verify screen functionality - again we really do not think it is the display, its probably the driver code. they can post the code they are using here, and the wiring diagram they are using - that would probably be the fastest way to debug

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