diff --git a/src/mame/handheld/teammate.cpp b/src/mame/handheld/teammate.cpp
index b33385ecf18..df3f90908cb 100644
--- a/src/mame/handheld/teammate.cpp
+++ b/src/mame/handheld/teammate.cpp
@@ -198,6 +198,7 @@ void teammate_state::teammate(machine_config &config)
 	F8(config, m_maincpu, 3600000/2); // R/C osc, approximation
 	m_maincpu->set_addrmap(AS_PROGRAM, &teammate_state::main_map);
 	m_maincpu->set_addrmap(AS_IO, &teammate_state::main_io);
+	m_maincpu->set_irq_acknowledge_callback("psu", FUNC(f38t56_device::int_acknowledge));
 
 	f38t56_device &psu(F38T56(config, "psu", 3600000/2));
 	psu.set_int_vector(0x20);