Troublesome PCBs

[camerart]

Hi,
I was working on a project, for a homemade drone, using 2x similar PCBs for BASE and REMOTE.

It uses Ublox GPS, BMP280, Iphone compass module, Nokia screen, joysticks, incrementle encoder, all working with SPI.

Each of these peripherals took some time to understand, and implement, and the whole project went for app 6x years, but even though all of the peripherals worked, it just wouldn't completely, and I had to give in and shelve it.

On an electrical forum, I watch, someone posted CODE for TFT screens, and with help this 'C' CODE was converted to BASIC (my only language), and we got the screens working intermittently.
I sent one of my project PCBs to one of the forum members, and neither of us could get the screens to work properly.

I got to thinking that it would be some problem with the PCBS that wasn't hobby level, but higher level, so I am asking: Is there a way to test a PCB, in a higher way, that at my level (pin to pin, and oscilloscope)?

By the way, both of the other 2x members working on this were successful with their breadboard and TTH PIC where my PCB has SMD PICs.

Cheers, Camerart.

[jpanhalt]

Hi camerart.  Good to see you.  I've been following that project.

I use solderable breadboards and had a somewhat similar problem a few years ago.  My circuit and  program worked weil with through hole parts (PIC 16F1xxx), but the manufactured board with an SMD MCU would not run off battery.  The schematic "looked" fine and DRG passed. Eventually after probing, I found a line on the schematic (battery ground) that looked like a legitimate connection but in fact was not a real net.  It was easily fixed.  As with most such problems, you feel a little foolish later. 

I don't know what to advise.  In my case, it was discovered by checking each layer separately in schematic editor.