I push it in and hold it and it works. Let go, it dies. Is there a replacement?

I push it in and hold it and it works. Let go, it dies. Is there a replacement?
@John England mine won't engage to power unit on, it only seems to have one position & that's Off. Did you ever fix your problem? I might just try to bypass the push button switch and make it On whenever power is plugged in.
