CoolArc200 Measurement Card

This is the quick live-reading card for the highest-value CoolArc200 input-sense and mode-state splits.

Use This Card When

the machine reads the wrong input class
OCV looks low but may be normal
fan or display behavior suggests a false control fault

Prove First

actual connected input voltage
clean clamp and output path
correct operating mode, including VRD state

Fast Measurement Card

Checkpoint	Where to measure or observe	Healthy expectation	If abnormal, keep diagnosis in...
Input-sense voltage	`J3` pins `2` and `7`	about `3.3 V` on `110 V` input and about `0.3 V` on `220 V` input	main-board input-detect or control indication branch
Display input indication	panel behavior on power-up	display matches the actual connected input class	control PCB if the sense voltage is correct but the display remains wrong
OCV in non-`VRD` mode	machine output after power-up and first weld	low at first can recover to normal high OCV after the first weld	state interpretation and sleep behavior before output-board repair
OCV in `VRD` mode	machine output	remains at the low safe-voltage level by design	normal `VRD` behavior, not a failed welding section
Fan startup	live observation at power-up	stable fan start without blink-only behavior	shorted fan or support branch before control-board replacement

Official Parts Shortcuts

Use these only after the live readings prove the complaint follows the adapter, TIG-kit, or external return-path branch.
CoolArc200 parts category: official parts path
TIG kit 07003750: official product page
230 V to 125 V input adapter 07001825: official product page
Ground clamp 07000462: official product page

Stop Rules

Stop and correct the mode misunderstanding first if low OCV is fully explained by VRD or first-weld wake-up behavior.
Stop and isolate the fan branch first if the display only blinks or twitches with no stable fan start.
Stop using the card and open the full guide if the sense voltage is correct but the rest of the symptom still does not fit the control branch cleanly.

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