Bench Test / WeldKing / CoolCut30

Test intent

Separate torch, air, and clamp faults from upper-board, capacitor-board, and inverter faults.
Confirm the 24 V support path and OCV behavior match the correct failure branch.
Verify stable start and transfer after repair without warm drift.

Tools and setup

Multimeter
Dry air source
Fresh SG55 front-end stack
Clean mild-steel coupon
Known-good work clamp

Pre-power checks

Check	Expected condition	Result
Torch front-end stack	correctly assembled, fresh consumables, no burned head	pass / fail
Clamp placement	bright metal, tight return path	pass / fail
Air quality	dry air and stable pressure under flow	pass / fail
HF gap before energizing	near the documented 1 mm branch note	pass / fail

Electrical checkpoints

Checkpoint	Expected value or behavior	Record actual
Upper-board green 24 V indicator	stays on continuously when 24 V is healthy
Fan behavior	stable, no abnormal collapse when upper-board feed is tested
OCV behavior at start attempt	clearly high, low, or absent and repeatable
HF behavior	visible or audible consistent HF on start attempt

Functional proof

Test	Pass condition	Result
Air sequence	normal preflow and postflow	pass / fail
Start test	repeatable HF and start on clean steel	pass / fail
Transfer test	transfers cleanly from pilot to cutting arc	pass / fail
Short cut	stable cut without dropout	pass / fail
Warm retest	no self-switching or support collapse after several starts	pass / fail

If it fails

No HF with high OCV: stay in relay or capacitor-board branch.
No HF with lower OCV: stay in inverter or upper-board branch.
Green 24 V light drops or the fan collapses during start: stay in the support-power branch before deeper output repair.
Pilot with no transfer: stay in torch front end, clamp, and air branch.
Fan or 24 V instability: stay in support-power branch.

Direct official parts pages

Use these only after the complaint has been proven to follow the SG55 torch-front-end or air branch.
CoolCut30 parts category: official CoolCut30 parts path
SG55 electrode 07Y2517003: official product page
SG55 tip 07Y2517005: official product page
SG55 nozzle 07Y2517004: official product page

Post-repair release

Signoff item	Result
Green 24 V indicator stays steady through start attempts	pass / fail
Stable start restored	pass / fail
Stable transfer restored	pass / fail
Short cut completed cleanly	pass / fail
No abnormal 24 V or fan drift after retest	pass / fail

Technician: __________ Date: __________ Serial or shop tag: __________