diff --git a/Components/6532/6532.hpp b/Components/6532/6532.hpp
index acfb7de78..bac2a3c3d 100644
--- a/Components/6532/6532.hpp
+++ b/Components/6532/6532.hpp
@@ -51,7 +51,7 @@ template <class T> class MOS6532 {
 					if(address & 0x10)
 					{
 						timer_.writtenShift = timer_.activeShift = (decodedAddress - 0x04) * 3 + (decodedAddress / 0x07);	// i.e. 0, 3, 6, 10
-						timer_.value = ((unsigned int)value << timer_.activeShift) + 2;
+						timer_.value = ((unsigned int)value << timer_.activeShift) ;
 						timer_.interrupt_enabled = !!(address&0x08);
 						interrupt_status_ &= ~InterruptFlag::Timer;
 						evaluate_interrupts();
@@ -119,7 +119,7 @@ template <class T> class MOS6532 {
 				timer_.value -= number_of_cycles;
 			} else {
 				number_of_cycles -= timer_.value;
-				timer_.value = 0x100 - number_of_cycles;
+				timer_.value = (0x100 - number_of_cycles) & 0xff;
 				timer_.activeShift = 0;
 				interrupt_status_ |= InterruptFlag::Timer;
 				evaluate_interrupts();
diff --git a/Machines/Atari2600/Atari2600.cpp b/Machines/Atari2600/Atari2600.cpp
index aa6e3fdd7..e779952df 100644
--- a/Machines/Atari2600/Atari2600.cpp
+++ b/Machines/Atari2600/Atari2600.cpp
@@ -63,6 +63,7 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
 
 	cycles_since_speaker_update_ += cycles_run_for;
 	cycles_since_video_update_ += cycles_run_for;
+	cycles_since_6532_update_ += (cycles_run_for / 3);
 
 	if(operation != CPU6502::BusOperation::Ready) {
 
@@ -218,7 +219,6 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
 	}
 
 	if(!tia_->get_cycles_until_horizontal_blank(cycles_since_video_update_)) set_ready_line(false);
-	cycles_since_6532_update_ += (cycles_run_for / 3);
 
 	return cycles_run_for / 3;
 }
diff --git a/OSBindings/Mac/Clock SignalTests/6532Tests.swift b/OSBindings/Mac/Clock SignalTests/6532Tests.swift
index 091fdfd0e..fa48039f5 100644
--- a/OSBindings/Mac/Clock SignalTests/6532Tests.swift	
+++ b/OSBindings/Mac/Clock SignalTests/6532Tests.swift	
@@ -21,10 +21,6 @@ class MOS6532Tests: XCTestCase {
 		with6532 {
 			// set a count of 128 at single-clock intervals
 			$0.setValue(128, forRegister:0x14)
-			$0.run(forCycles: 1)
-
-			// one cycle later the timer should still contain 128
-			$0.run(forCycles: 1)
 			XCTAssertEqual($0.value(forRegister: 4), 128)
 
 			// run for one more clock and the count should now be 127
@@ -52,10 +48,6 @@ class MOS6532Tests: XCTestCase {
 		with6532 {
 			// set a count of 28 at eight-clock intervals
 			$0.setValue(28, forRegister:0x15)
-			$0.run(forCycles: 1)
-
-			// one cycle later the timer should still contain 28
-			$0.run(forCycles: 1)
 			XCTAssertEqual($0.value(forRegister: 4), 28)
 
 			// one further cycle and the timer should hit 27
@@ -99,9 +91,6 @@ class MOS6532Tests: XCTestCase {
 			$0.setValue(1, forRegister:0x1c)
 			$0.run(forCycles: 1)
 
-			// run for two clocks and the count should now be zero
-			$0.run(forCycles: 2)
-
 			// interrupt shouldn't be signalled yet, bit should not be set
 			XCTAssert(!$0.irqLine, "IRQ line should not be set")
 			XCTAssert($0.value(forRegister: 5) == 0x00, "Counter interrupt should not be set")