diff --git a/Machines/Enterprise/Dave.cpp b/Machines/Enterprise/Dave.cpp
index f3b7938cf..81b0f64da 100644
--- a/Machines/Enterprise/Dave.cpp
+++ b/Machines/Enterprise/Dave.cpp
@@ -234,12 +234,14 @@ void TimedInterruptSource::write(uint16_t address, uint8_t value) {
 	}
 }
 
+// TODO: don't muck about with update_channel if channels have a reload value of 0.
+
 void TimedInterruptSource::update_channel(int c, bool is_linked, int decrement) {
 	if(channels_[c].sync) {
 		channels_[c].value = channels_[c].reload;
 	} else {
 		channels_[c].value -= decrement;
-		if(channels_[c].value < 0) {
+		while(channels_[c].value < 0) {
 			channels_[c].value += channels_[c].reload + 1;
 
 			if(is_linked) {
@@ -248,7 +250,7 @@ void TimedInterruptSource::update_channel(int c, bool is_linked, int decrement)
 				}
 				programmable_level_ = channels_[c].level;
 			}
-			channels_[c].value ^= true;
+			channels_[c].level ^= true;
 		}
 	}
 
diff --git a/Machines/Enterprise/Dave.hpp b/Machines/Enterprise/Dave.hpp
index cf3d518ea..b0d986e1f 100644
--- a/Machines/Enterprise/Dave.hpp
+++ b/Machines/Enterprise/Dave.hpp
@@ -147,7 +147,7 @@ class TimedInterruptSource {
 		} rate_ = InterruptRate::OnekHz;
 
 		struct Channel {
-			uint16_t value = 100, reload = 100;
+			int value = 100, reload = 100;
 			bool sync = false;
 			bool level = false;
 		} channels_[2];
diff --git a/Machines/Enterprise/Enterprise.cpp b/Machines/Enterprise/Enterprise.cpp
index 87ecbe20a..bf2baff9f 100644
--- a/Machines/Enterprise/Enterprise.cpp
+++ b/Machines/Enterprise/Enterprise.cpp
@@ -399,10 +399,6 @@ template <bool has_disk_controller> class ConcreteMachine:
 							interrupt_mask_ = *cycle.value & 0x55;
 							interrupt_state_ &= ~*cycle.value;
 							update_interrupts();
-
-							if(interrupt_mask_ & 0x41) {
-								printf("Unimplemented interrupts requested: %02x\n", interrupt_mask_ & 0x45);
-							}
 						break;
 						case 0xb5:
 							active_key_line_ = *cycle.value & 0xf;