Identifying transistor an6a and can it cause high voltage across

[champagne_charly]

Hi, i hope somebody an help.

Trying to repair a couple of circuit boards.. from bo bluetooth speaker .beoplay a2

Caps on one were fried when I got it. Also noticed that a transistor was also tried.

I had removed the caps 10uf 16v on the other which had been working previously. My intention was just to see how the failty board should have been before it was scortched by the burning cap..

So I fixed the cap on the good board.. or what was the good board. Plugged it in and it sizzles.. checked the voltage and it was 21v so for a 16v cap no surprise.. however dc power supply is 15v and that is what it puts out.. went away and came back.. started testing the known faulty board and thats when i discovered the burnt out transistor. Took some pics from board 2 to try and find a replacement. Went back and tested board 2 and voltage was at 15v. Confused and thinking i had just lost it added a new couple of caps.. and started testing again.. this time caps were stable no pop but device wasn't being recognised by computer... out of nowhere there was a little sizzle from the other side of the board and the other transistor had failed..

Now two issues.. fortunately I took a pic however I can't find any ref to that part. What appeared to be written was AN6A
Board ref q5. I checked to see if any other tr existed on the board of same coding but nothing.
2nd thing is can the increase in voltage be caused by a faulty tr?

Any advice assistance would be much apreciated.

 

[champagne_charly]

Trying to grasp how on earth the voltage would increase... and then thought and poss the reason for the 2 readings... I guess the 5v from USB + 15v from psu. Although that's still only 20v.. as you can tell I'm an utter newb to electronics.