Sounds like the CW-80 is working correctly, but was not working correctly before you opened it.
Our hobby transformers are intended to work in this manner:
The direction button is a NC (normally closed) switch. It interrupts power to the track. No electricity should flow with it depressed since the circuit is open.
The whistle and bell button will add a DC offset to the track and should not work independently of the throttle i.e. with the throttle "off" no DC voltage should be sent to the track; with the throttle "on" the whistle or bell (if equipped) should be activated by the DC offset when the appropriate button is depressed.
