Simplex 4005 won't sound alarm

I just started work in an institution that is still running a Simplex 4005 panel and when a zone signals an alarm the panel itself sounds but none of the strobes/alarms are activating. Does anyone have an idea of what might be causing this?

See if you have a NAC card model 565-477. However the card can be used as a dry relay or a signal circuit, depending of how the black cube is set on the card. Be carful sometimes they used this card as elevator recall or monitoring points to the Dialer.

Thanks for the help, that unit does have a 565-477 (4005-9805) card. It used to set off the strobe/alarms in the past but no longer does. I’ve checked all the fuses on the card and they are intact.