Hypothetical Scenario

[macacob]

If one were to solder the TL072 backwords, and then install it in a C64 and turn it on, what other components of the SKPico with onboard DAC might get fried? Asking for a friend. (Thankfully no damage to the C64)

[frntc]

Hm... I have no empirical values ;-) I think there's a good chance that only the TL072 is damaged. Have you tried replacing it (it's probably fried, at least you, well your friend, swapped +5V and GND)

[macacob]

Hmm, good suggestion. I will go back and triple check what I installed on the pico, but I am 99% sure it is the same firmware I have on prior builds which are working.

[macacob]

Soooo, both the SKPico board and the Pico clone board are faulty. the RGB Pico clone does not work with my known good SKpico build, and my known good RGB Pico clone will not work with my faulty SKpico build. not a firmware issue I guess, something really did get damaged.

[frntc]

Is there just no sound, or does the SKpico not even launch the config too with the known-good Pico clone?

[macacob]

With a known good Pico there is no sound but the config launches.

[frntc]

Then the CBTD3861 should be good, but the DAC is not...