diff --git a/src/emu/cpu/tms9900/tms9995.c b/src/emu/cpu/tms9900/tms9995.c
index a73d6f924f0..60e61cd7338 100644
--- a/src/emu/cpu/tms9900/tms9995.c
+++ b/src/emu/cpu/tms9900/tms9995.c
@@ -125,6 +125,7 @@ enum
 
 // Log addresses of executed opcodes
 #define TRACE_EXEC 0
+#define TRACE_CYCLES 0
 
 // This is the previous debugging approach which will be replaced by the
 // specific switches above
@@ -1501,7 +1502,7 @@ void tms9995_device::next_command()
 void tms9995_device::command_completed()
 {
 	// Pseudo state at the end of the current instruction cycle sequence
-	if (VERBOSE>4)
+	if (TRACE_CYCLES)
 	{
 		LOG("tms9995: +++++ Instruction %04x (%s) completed", m_instruction->IR, opname[m_instruction->command]);
 		int cycles =  m_first_cycle - m_icount;
diff --git a/src/mess/drivers/ti99_8.c b/src/mess/drivers/ti99_8.c
index 67971c86ca6..bd79e508e82 100644
--- a/src/mess/drivers/ti99_8.c
+++ b/src/mess/drivers/ti99_8.c
@@ -1039,7 +1039,7 @@ MACHINE_RESET_MEMBER(ti99_8_state, ti99_8)
 static MACHINE_CONFIG_START( ti99_8_60hz, ti99_8_state )
 	/* basic machine hardware */
 	/* TMS9995-MP9537 CPU @ 10.7 MHz */
-	MCFG_TMS99xx_ADD("maincpu", TMS9995, 10738635, memmap, crumap, ti99_8_processor_config)
+	MCFG_TMS99xx_ADD("maincpu", TMS9995, XTAL_10_738635MHz, memmap, crumap, ti99_8_processor_config)
 	MCFG_MACHINE_START_OVERRIDE(ti99_8_state, ti99_8 )
 	MCFG_MACHINE_RESET_OVERRIDE(ti99_8_state, ti99_8 )
 
@@ -1047,7 +1047,7 @@ static MACHINE_CONFIG_START( ti99_8_60hz, ti99_8_state )
 	MCFG_TI998_ADD_NTSC(VIDEO_SYSTEM_TAG, TMS9118, ti99_8_tms9118a_interface)
 
 	/* Main board */
-	MCFG_TMS9901_ADD( TMS9901_TAG, tms9901_wiring_ti99_8, 2684658.75 )
+	MCFG_TMS9901_ADD( TMS9901_TAG, tms9901_wiring_ti99_8, XTAL_10_738635MHz/4.0)
 	MCFG_MAINBOARD8_ADD( MAINBOARD8_TAG, mapper_conf )
 	MCFG_TI99_GROMPORT_ADD( GROMPORT_TAG, console_cartslot )
 
@@ -1084,7 +1084,7 @@ MACHINE_CONFIG_END
 static MACHINE_CONFIG_START( ti99_8_50hz, ti99_8_state )
 	/* basic machine hardware */
 	/* TMS9995-MP9537 CPU @ 10.7 MHz */
-	MCFG_TMS99xx_ADD("maincpu", TMS9995, 10738635, memmap, crumap, ti99_8_processor_config)
+	MCFG_TMS99xx_ADD("maincpu", TMS9995, XTAL_10_738635MHz, memmap, crumap, ti99_8_processor_config)
 	MCFG_MACHINE_START_OVERRIDE(ti99_8_state, ti99_8 )
 	MCFG_MACHINE_RESET_OVERRIDE(ti99_8_state, ti99_8 )
 
@@ -1092,7 +1092,7 @@ static MACHINE_CONFIG_START( ti99_8_50hz, ti99_8_state )
 	MCFG_TI998_ADD_PAL(VIDEO_SYSTEM_TAG, TMS9129, ti99_8_tms9118a_interface)
 
 	/* Main board */
-	MCFG_TMS9901_ADD( TMS9901_TAG, tms9901_wiring_ti99_8, 2684658.75 )
+	MCFG_TMS9901_ADD( TMS9901_TAG, tms9901_wiring_ti99_8, XTAL_10_738635MHz/4.0 )
 	MCFG_MAINBOARD8_ADD( MAINBOARD8_TAG, mapper_conf )
 	MCFG_TI99_GROMPORT_ADD( GROMPORT_TAG, console_cartslot )
 
diff --git a/src/mess/machine/ti99/grom.c b/src/mess/machine/ti99/grom.c
index 1fe3b5223b0..fc168e15960 100644
--- a/src/mess/machine/ti99/grom.c
+++ b/src/mess/machine/ti99/grom.c
@@ -87,8 +87,7 @@
 #include "emu.h"
 #include "grom.h"
 
-#define LOG logerror
-#define VERBOSE 1
+#define TRACE_ADDRESS 0
 
 /*
     Constructor.
@@ -139,6 +138,7 @@ READ8Z_MEMBER( ti99_grom_device::readz )
 		{
 			// GROMs are buffered. Data is retrieved from a buffer,
 			// while the buffer is replaced with the next cell content.
+			if (TRACE_ADDRESS) if (m_ident==0) logerror("grom0: %04x = %02x\n", m_address-1, m_buffer);
 			*value = m_buffer;
 			// Get next value, put it in buffer. Note that the GROM
 			// wraps at 8K boundaries.
@@ -191,6 +191,7 @@ WRITE8_MEMBER( ti99_grom_device::write )
 				m_buffer = m_memptr[m_address-(m_ident<<13)];
 			}
 			m_waddr_LSB = false;
+			if (TRACE_ADDRESS) if (m_ident==0) logerror("grom0: %04x\n", m_address);
 		}
 		else
 		{
diff --git a/src/mess/machine/ti99/ti99defs.h b/src/mess/machine/ti99/ti99defs.h
index d6c5f3a531f..b1cf956075d 100644
--- a/src/mess/machine/ti99/ti99defs.h
+++ b/src/mess/machine/ti99/ti99defs.h
@@ -32,7 +32,8 @@
 #define JOYPORT_TAG     "joyport"
 #define VDP_TAG         "vdp"
 
-#define GROMFREQ 10700000.0/24
+#define VDPFREQ XTAL_10_738635MHz
+#define GROMFREQ VDPFREQ/24
 
 // TI-99/8
 #define SRAM_TAG        "sram8"