I am trying to mechanize a harpsichord by using solenoids to activate the keys. I have purchased some cheap solenoids (60+!) but I find now that the release time is quite substantial - I mean like 1 to 1 and a half seconds. I hung the solenoid from a support, put some weight on the plunger, activated the solenoid and then deactivated it to allow gravity to pull it down. The plunger noticeably delays before falling. They are 12V solenoids and take about 0.5A. I have included a IN4001 diode in parallel with the solenoid and am testing them with a 12V power supply. I've read that a zener diode in series with the IN4001 can help it release quicker, but it seems like that will help decrease the time from, for example, 11msec down to 3msec. I'm far away from that! Is there something else going on here?