diff --git a/src/emu/drivers/xtal.h b/src/emu/drivers/xtal.h
index 8d0479dd461..6170f4203e9 100644
--- a/src/emu/drivers/xtal.h
+++ b/src/emu/drivers/xtal.h
@@ -196,6 +196,7 @@ enum
 	XTAL_25_447MHz      = 25447000,     /* Namco EVA3A (Funcube2) */
 	XTAL_25_590906MHz   = 25590906,     /* Atari Jaguar NTSC */
 	XTAL_25_593900MHz   = 25593900,     /* Atari Jaguar PAL */
+	XTAL_26MHz          = 26000000,     /* Gaelco PCBs */
 	XTAL_26_601712MHz   = 26601712,     /* Astro Corp.'s Show Hand, PAL Vtech/Yeno Socrates (6x PAL subcarrier) */
 	XTAL_26_66666MHz    = 26666666,     /* Irem M92 but most use 27MHz */
 	XTAL_26_686MHz      = 26686000,     /* Typically used on 90's Taito PCBs to drive the custom chips */
@@ -221,6 +222,7 @@ enum
 	XTAL_33_333MHz      = 33333000,     /* Sega Model 3 CPU board, Vegas */
 	XTAL_33_833MHz      = 33833000,
 	XTAL_33_8688MHz     = 33868800,     /* Usually used to drive 90's Yamaha OPL/FM chips with /2 divider */
+	XTAL_34MHz          = 34000000,     /* Gaelco PCBs */
 	XTAL_36MHz          = 36000000,     /* Sega Model 1 video board */
 	XTAL_38_76922MHz    = 38769220,     /* Namco System 21 video board */
 	XTAL_40MHz          = 40000000,
diff --git a/src/mame/drivers/gaelco2.cpp b/src/mame/drivers/gaelco2.cpp
index b68436bc670..88d260867b8 100644
--- a/src/mame/drivers/gaelco2.cpp
+++ b/src/mame/drivers/gaelco2.cpp
@@ -176,7 +176,7 @@ INPUT_PORTS_END
 
 static MACHINE_CONFIG_START( maniacsq )
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", M68000, 26000000/2)     /* 13 MHz? */
+	MCFG_CPU_ADD("maincpu", M68000, XTAL_26MHz / 2)     /* 13 MHz? */
 	MCFG_CPU_PROGRAM_MAP(maniacsq_map)
 	MCFG_CPU_VBLANK_INT_DRIVER("screen", gaelco2_state,  irq6_line_hold)
 
@@ -443,11 +443,11 @@ ROM_END
 
 static MACHINE_CONFIG_START( play2000 )
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", M68000, 11059200)     /* or from the 34MHz? */
+	MCFG_CPU_ADD("maincpu", M68000, XTAL_11_0592MHz)     /* or from the 34MHz? (34MHz drives the CG-1V-149 PLD?) */
 	MCFG_CPU_PROGRAM_MAP(play2000_map)
 	MCFG_CPU_VBLANK_INT_DRIVER("screen", gaelco2_state,  irq6_line_hold)
 
-	// MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, 11059200) /* ? */
+	// MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL_11_0592MHz) /* 11.0592MHz */
 	// MCFG_DEVICE_ADDRESS_MAP(0, mcu_hostmem_map)
 
 	/* video hardware */
@@ -540,7 +540,7 @@ INPUT_PORTS_END
 
 static MACHINE_CONFIG_START( bang )
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", M68000, 30000000/2)         /* 15 MHz */
+	MCFG_CPU_ADD("maincpu", M68000, XTAL_30MHz / 2) /* 15 MHz */
 	MCFG_CPU_PROGRAM_MAP(bang_map)
 	MCFG_TIMER_DRIVER_ADD_SCANLINE("scantimer", bang_state, bang_irq, "screen", 0, 1)
 
@@ -787,7 +787,7 @@ INPUT_PORTS_END
 
 static MACHINE_CONFIG_START( alighunt )
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", M68000, 24000000/2)         /* 12 MHz */
+	MCFG_CPU_ADD("maincpu", M68000, XTAL_24MHz / 2)         /* 12 MHz */
 	MCFG_CPU_PROGRAM_MAP(alighunt_map)
 	MCFG_CPU_VBLANK_INT_DRIVER("screen", gaelco2_state,  irq6_line_hold)
 
@@ -819,7 +819,7 @@ static MACHINE_CONFIG_START( alighunt )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( alighunt_d5002fp, alighunt )
-	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL_24MHz / 2) /* ? */
+	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL_24MHz / 2) /* 12 MHz */
 	MCFG_DEVICE_ADDRESS_MAP(0, mcu_hostmem_map)
 MACHINE_CONFIG_END
 
@@ -1084,7 +1084,7 @@ INPUT_PORTS_END
 
 static MACHINE_CONFIG_START( touchgo )
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", M68000, 32000000/2)         /* 16 MHz */
+	MCFG_CPU_ADD("maincpu", M68000, XTAL_32MHz / 2)         /* 16 MHz */
 	MCFG_CPU_PROGRAM_MAP(touchgo_map)
 	MCFG_CPU_VBLANK_INT_DRIVER("lscreen", gaelco2_state,  irq6_line_hold)
 
@@ -1132,7 +1132,7 @@ static MACHINE_CONFIG_START( touchgo )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( touchgo_d5002fp, touchgo )
-	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL_24MHz / 2) /* ? */
+	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL_40MHz / 4) /* 10MHz? - Not verified */
 	MCFG_DEVICE_ADDRESS_MAP(0, mcu_hostmem_map)
 MACHINE_CONFIG_END
 
@@ -1330,7 +1330,7 @@ INPUT_PORTS_END
 
 static MACHINE_CONFIG_START( snowboar )
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", M68000, 30000000/2)         /* 15 MHz */
+	MCFG_CPU_ADD("maincpu", M68000, XTAL_30MHz / 2)         /* 15 MHz */
 	MCFG_CPU_PROGRAM_MAP(snowboar_map)
 	MCFG_CPU_VBLANK_INT_DRIVER("screen", gaelco2_state,  irq6_line_hold)
 
@@ -1573,11 +1573,11 @@ INPUT_PORTS_END
 
 static MACHINE_CONFIG_START( wrally2 )
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", M68000, 26000000/2)         /* 13 MHz */
+	MCFG_CPU_ADD("maincpu", M68000, XTAL_26MHz / 2) /* 13 MHz */
 	MCFG_CPU_PROGRAM_MAP(wrally2_map)
 	MCFG_CPU_VBLANK_INT_DRIVER("lscreen", gaelco2_state,  irq6_line_hold)
 
-	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL_24MHz / 2)
+	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL_34MHz / 4) /* 8.5MHz? (or 13MHz - 26MHz/2) - Not verified */
 	MCFG_DEVICE_ADDRESS_MAP(0, mcu_hostmem_map)
 
 	MCFG_DEVICE_ADD("mainlatch", LS259, 0)