Firmware issues of fried TLC5940?

[IhnnChocoFarms]

Hey Tim !
Ruben from Cubusynth allowed me to get one of his eurorack conversion prototype of this module.
I finished building it entirely but for some reason I'm unable to get any responses from the 4 LEDs banks.
When powered on only one of the LEDs of each banks light up, sometimes I get weird behaviors like blinking second leds or stuff. Also the LEDs don't respond in any way to the brightness controls. I checked the outputs of the jacks and they are correctly outputing the expected triggers and the adafruit seems to correctly translate the encoder inputs. So the arduino is correctly running the code.
At first I guessed my TLCs where fried but I checked their pins and they don't bleed current in any way and are correctly grounded, I also checked their outputs and they are quite normal expect for the lit up leds.
So it's possibly a firmware installation issue, there's no compilation errors and files are correctly linked, do you think I'll have more luck using the last TLC5970 libraries or just keep using your forked library?
The arduino nano not having debbug functionality is making it quite hard to check if the TLCs are correctly initialized.
The module is also fitted with the CV expander btw.
It's my first arduino nano powered module so it's really possible I messed something up while uploading the code and libraries.
Thanks for the great modules !!
Cheers
Ihnn_

[TimMJN]

Hi Ihnn,

Obviously I'm not too familiar with the Cubusynth version, but let me try to give you some pointers.

If the output triggers work like expected, and the encoders and CV inputs work, I'm confident it's not a firmware issue.

First of all, the LED drivers should be TLC5940, not TLC5970. Hope you got that right. Then, when you say "their outputs are quite normal", what do you mean? Did you hook up a scope and confirm they are driving high/low when they should? Or do you mean they are within the supply range and nothing is producing any smoke?

Are they THT or SMD? The THT version of this IC is no longer in production, and aliexpress/amazon/the likes are riddled with fakes. You should be looking for "new old stock" product, and expect to pay a pretty penny (I've seen €20+ per IC). Also if they're SMD, did you get them from a reliable supplier? I've been throwing in little adapter boards with by PCBs to use the SMD version on the DIP footprint.

If you're confident they're genuine, can you take one out and create a little test setup? An arduino, led driver and a few leds on a breadboard, and run a simple example code? Also, are you sure your LEDs aren't on backwards?

Hope this gives you some directions to look at!

Tim