Borgelt B50 Help Needed

I am trying to install an older Borgelt B50 (SN9910126) and need some
help. This is an older model than the B50 manuals on the Borgelt web
page.

1. I need a wiring diagram for this older B50. It has a DB15 on the
back.

2. The speaker makes noise even when the tone should be in deadband.
It is cut off (quieter) compared to the normal level but still
audible. I would like to know if anyone else has dealt with this and
if there is a fix.

Thanks,

Tim