Thanks, Jim.
I have replaced the LCD female headers, but nothing has changed.

  Grogster said  

@ Jim - You asked me to post the images of the old and new PCB.  Did you see anything obviously wrong on my layouts that you would have changed?

The one thing I noticed looking at the images is the GND and CS pins appear to be connected to a copper pour.  Is that section of copper pour truly grounded?

--Curtis

GDay Grogster, All,

Check that the TFT GND pin is actually connected to GND, by adding the switch you ‘may’ have an isolated GND pour meaning that GND on the TFT is at actually system GND.

It is hard to follow the traces with the colour choices but it is basically the same as the original except for the switch and different HC12 layout.

Kind Regards,

Mick (the big one)



.

Good point, but yes - the LCD GND and the CS pin are connected to the common ground.





Once I unearth my DSO next week, I will try to get a screenshot of the D/C line that Jim wanted.

Hi Grogster,

Looking further it does seem that a GND does connect to the Pic and the TFT but that image above is your old version without the new switch.

This is a curious issue.

Suggestions are to minimise it by removing sections you don’t need (like the SD connector and any HC12)

Not much to minimise though.

Are you able to post images of top and bottom copper without the copper pours and individual copper layers (with pours) and without the other layer showing? That would make tracing the wiring easier.

Regards,

Mick



.
Edited 2024-04-21 11:01 by bigmik

Grogster,

Another thought.

Are the 2 capacitors on the VReg actually 10uF? You may have accidentally used 10nf maybe?

I can’t see any logical reason for one board to work and the other not to.

Mick

I did ask about the capacitor and Grogster said it was OK. The PIC does run and drive the LEDs but I guess it could be marginal? Could be worth trying another.

Bill

The regulator pads look right for the SOT-223 package. I hope that's the one used here as the SOT-89 is different.

Yes, SOT-223.  

I'll upload the images Mick asked for later, but have some other work to do today, so that will be later on tonight my time.

Any resolution ?
Without a deep dive my only thought is that the blue pour connections running between the 170 pins seem thin, maybe one is intermittent or high resistance.
Displays can be a pain.

(ed - what size is the display ? I got the impression it was 2.2 ? As it happens I have a similar display (2.2") that works OK but the controller is ILI9225.)
Edited 2024-04-26 11:46 by zeitfest

No, and as it is relatively low-priority compared to other paid work I needed to get done, it has basically just sat on the bench for the last few days.  

I have not forgotten it though, and will get back to it when I can - which should be sometime next week when I expect to have a little more time to tinker.

LCD is an ILI9341, 2.2" without touch.