MAG255 Board Opening Map

This is the fast internal opening map for MAG255 once crater-fill, gun, spool-gun, and drive-roll branches are already bounded.

Open Only After Proving

base plain-steel MIG baseline has been proven or ruled out
crater-fill behavior has already been captured and simplified
spool-gun complaints are already separated from the base gun
clamp, polarity, and current path are already clean
no-trigger tip-spark behavior is already separated from branch-specific spool-gun complaints

First Internal Targets

Board or internal group	Open first when...	Key connector or checkpoint	Best local file to open first
Crater-fill control branch	wire keeps creeping after stop	crater-fill behavior and disable logic	`Mag255_disable_craterfill.pdf`
Discharge-path branch	sparks appear at the wire tip without trigger command	discharge resistor and safe bleed path	workbook sheet `MAG255`
Spool-gun control branch	base gun is healthy but spool gun still will not weld	pins `1` and `9` with spool-gun branch selected	`mag255manual.pdf` and workbook
Capacitor or ripple branch	unstable arc persists on a proven base gun	output smoothness and capacitor condition	workbook sheet `MAG255`

Connector and Board-Family Reminders

Do not treat crater-fill symptoms like random feed faults. MAG255 has a named crater-fill branch.
Keep spool-gun-only complaints outside the chassis until base MIG is proven healthy.
Keep discharge-path symptoms separate from live-weld instability. They are not the same branch.
Do not open the machine while chart-correct plain-steel base MIG is healthy and only the spool-gun branch still fails.

External Parts Exit Paths

If the opening pass shows the complaint still follows the external gun, spool gun, or drive-roll branch, leave the board path and use the official ordering flow instead.
MAG255 parts category: official parts path
SpoolKing24D spool gun 07NS1000: official product page
U-groove aluminum drive roll 07000302: official product page

Stop Rules

Stop and isolate crater-fill first if wire creep changes when crater-fill is simplified.
Stop and go back to the external path if base MIG is healthy and only the spool gun still fails.
Stop and return to the full guide if discharge, stop behavior, and arc evidence still overlap after the first opening pass.

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