Light Phaser SNAC drift compared to real hardware/MegaSG + DAC

[YLFAndy]

Description:
The light phaser shows a pronounced drift via SNAC on the SMS core. The drift appears in all games and is more pronounced* on the left hand side of the screen, and is non-existent on the right hand side (linear reduction in drift with X axis).
*Panasonic BVM RGB with composite sync, 17" and Toshiba 20AF43 both display the issue, Toshiba over straight composite as well.

Prerequisites:
A MiSTer and appropriate SNAC adapter, Sega light phaser, CRT TV. SNAC enabled and jumpered properly on the I/O board.

Repro Steps:

1. Launch a game with easily viewable drift. Example: Gangster Town (The name entry screen is a static grid).
2. Fire the phaser to start the game.
3. Fire the phaser at the first column of letters at close range.

Result: The phaser registers far to the left of the desired target point.

4. Fire the phaser at the last column of letters at close range.

Result: The phaser registers very accurately to center.

Expected result:
The phaser should retain accuracy along the X axis over SNAC.

Other notes:

Other systems tested -

Original Master System Power Base hardware (NTSC, NA, Composite) - Result: Consistent accuracy across the X axis.

MegaSG + DAC + SOG - Result: Consistent accuracy across the first 80% of the X axis, slight drift right and down on the right edge of the screen.