MAG251 Measurement Card

This is the quick live-reading card for the highest-value MAG251 ripple, feed-direction, and spool-gun branch splits.

Use This Card When

the arc feels rough or unstable
wire feed acts wrong after board work
the complaint follows only the spool-gun branch

Prove First

correct base-gun setup with plain-steel wire
correct polarity and lead placement
known-good gun path before spool-gun proving

Fast Measurement Card

Checkpoint	Where to measure or observe	Healthy expectation	If abnormal, keep diagnosis in...
Solenoid branch on trigger	gas-valve branch during trigger	roughly the documented MAG-family level, not dead or erratic	gas-valve or control branch
Arc smoothness on short weld	live weld behavior	no heavy ripple feel or harsh unstable buzz	capacitor condition branch
Feed direction after service	wire direction on trigger	correct forward feed	board-install or motor-direction branch
Spool-gun branch only	compare base gun to spool gun	base gun proves first, spool-gun complaint stays isolated	spool-gun and drive-roll branch

Official Parts Shortcuts

Use these only after the readings prove the complaint follows the external gun, spool-gun, or drive-roll branch.
MAG251 parts category: official parts path
SpoolKing24D spool gun 07NS1000: official product page
MAG251 drive-roll family including 072611011 and 07NS1005: official category page

Stop Rules

Stop and correct feed direction first if it changed after board work.
Stop and keep the diagnosis external if the base gun is healthy and only the spool gun fails.
Stop using the card and open the full guide if gas, feed, and ripple branches do not align to one clear path.

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