I have designed a little circuit and got some (5) PCBs printed and assembled in china and unfortunately I made a mistake when I transferred my prototype circuit into my schematic. Even less fortunate I only realized that mistake after I tried to test the boards at home, not before I ordered them.
I mistakenly confused the emitter and collector here. The INP should go into the collector and DT into the emitter.
since I already have some readily printed and assembled boards here this poses a challenge to me. I don't want to spend another 140 bucks for a minor mistake (and I'm not even sure if I didn't make another mistake here).
On one board I already removed the transistor. I only have normal, let's call it breadboard sized transistors at home. I tried to bend one's (TIP120 - Not the correct specs but worth a short try if it's feasible at all) connectors into the correct pinout positions and solder it to the board with more flexible wires in between, but I think my motoric abilities are not sufficient enough for that kind of task (don't know if you can grasp the tiny dimensions from that picture, but it's super small).
A second idea was to find a transistor that has its emitter and collector flipped (where the emitter is on the top center and collector is on the bottom left). I thought of a PNP transistor but that wouldn't suit my circuit either. As for NPN I couldn't find a suitable replacement for the given transistor and it's form/package (SOT-23).
I want to try a smaller transistor as opposed to the TIP 120 (like the SS8050-TA in TO-92). In the meantime, does anyone have experience with that and maybe even know a transistor (or type of transistor) that i could search for? I would also be happy to try different approaches to solve that problem.
Thank you very much for your help!
** EDIT **
for completeness and to make it easier to read in future I tried to visualize the pin situation.
- BLUE is the correct transistor SOT-23 pin out
- RED is my faulty connection, aka how the transistor should be connected., resulting into the flipping of C and E, indicated by the blue arrow