Pointing out screen issue on PFM3

[served]

Hello,

I have encountered some issues with the TFT screen in PreenFM3.

When you build it from DIY kit yourself, make sure you isolate the screws and nuts from the pcb where the traces are very close to the mounting holes.
If that PCB lacquer fails to isolate. You are feeding the TFT datalines with noise. And this causes issues.






Insert plastic isolation washer between the nut and pcb.

Pictures are taken from the first patch PCB-s. But the next patch still has them too close and the nut will touch one of the traces.

[ericd]

Hi Ardi

Would this be an issue on the first batch of assembled units you made? What's the size of that plastic isolation washer (if we need to get one?)

Thanks

[served]

My assembled units should all have it.
But you can have a look just to be sure.
Its a nut that fits m3 polt.

[forestcaver]

Hello,

I have encountered some issues with the TFT screen in PreenFM3.

On that board it looks like you’ve got at least one cold solder joint (especially the one closest to the mcu) on the tft header which may be more of an issue... it’s also worth getting rid of the flux on the header as well - that may also cause issues. (But it’s a good point about the traces - I use plastic nuts or washes anywhere near traces as well)

[served]

No cold solder. And no flux issues. I am using special no-clean solid rosin flux that doesnt need cleaning. It cools down and cristalyses.
So there is no issues on the Flux conductivity. Its also very hard to clean.

I am not reporting issue with my TFT, its more a report on the solution that I think everyone should pay attention to.
This should remove one non-obvious issue that may happen.

[Xavier]

Can someone describes if that actually fixes a problem ?

Is there a problem that occurs when the screw is in place, that is fixed when the screw is removed ?
Or is it just a precaution to take in case of bad solder mask on the PCB ?

[served]

I can confirm that when I removed the nut the issue dissapared.

[Xavier]

I can confirm that when I removed the nut the issue dissapared.

As i'm trying to understand the TFT portem, please give me more details.

Can you describe what issue you're talking about ?
How often it occures ?

And if you remove the metal nut the problem is completely fixed ?
And with the plastic washer, the problem is also fixed ?