Mike58
New Member
Hello everyone. I'm hoping for some help. I have an old Unitrol 800 series siren that has 2 blown SP3099 power output transistors. They are a TO-3 style matched pair located on the bottom of the unit. Does anyone know of equivalent replacements for these transistors? I can't seem to find them listed on data sheets anywhere. There is a third transistor, a 2N3055 NPN that checks out ok with a dvm in diode mode. The two SP3099's (PNP i'm guessing) are open circuit so i'm assuming they're blown and hoping equivalent replacements are available. The siren powers up ok and I can hear it faintly from a small piezo located on the internal circuit board. I just have no amplification. Also, does anyone have a manual in pdf for this unit? A wiring diagram and schematic would sure be helpful providing I can replace the two bad transistors. Any help and ideas are greatly appreciated. Thanks in advance.
-Mike
-Mike