Troubleshooting a dartboard

[Tiller]

Hello,

My friend has a dartboard for which he lost the AC adapter. While trying some random AC adapter, he probably broke the board and now I'm trying to troubleshoot it with my limited knowledge.

The main issue is - I think - that the board took a 19V input instead of the expected 5V (yes.. I know...). There is a chance (50% ?) that the polarity was also reversed (+ on - and - on +). From there, I swapped the 19V he put by a 5V but got no response from the board, before realizing the polarity was reversed and then I put everything in its proper place.

So now the board is properly powered (5V DC) and some LED lights up when I plug it ( https://stuff.stooit.com/d/1/598596612dbb8/20170804_194402.jpg ), but it doesn't do much more. There was a capacitor near the input that had a bad look (it was bubbled on the bottom) so I replaced it (replaced a 19V 220uF cap by a 19V 330uF) but I still have the same result. I went ahead and replaced all capacitors of the board (there was ~6 104 ceramic capacitors, that I replaced by new 104 ceramic capacitors), but still the same result.

With a multimeter, I checked all resistors on the board and they're OK (or looks like it). I also tried to test the transistors but I wasn't sure how to test it. I simply tried to see if current flowed from the base towards the 2 other pins.

And there I am... I'm out of idea and I'm afraid that it might be the microcontroller that's dead... So before repurposing the board (I'll try to replace the microcontroller with an arduino) I just wanted your opinion on what might be the issue there...

Here is the top of the board: https://stuff.stooit.com/d/1/598596469147e/20170805_115148.jpg
And here's the bottom: https://stuff.stooit.com/d/1/5985962a54e51/20170805_115209.jpg

Thanks.