MK120 receiver stopped working


I tried using a 9V 200ma power supply with the MK120. The transmitted was fine with it, but the receiver did not seem to like it, and stopped working. Trying the transmitter with batteries, I can see it active in a smartphone camera. The receiver does not seem to work any more.

I think the power supply may not have been well-regulated. What can I test to see if there is a part I can replace and get the receiver working again?


I would replace every semiconductor, that is the quickest way to fix this problem.
All parts in this kit are cheap and commonly available.