E337 · Source-scoped pinout variants

3-pin PC fan connector / motherboard header engineering reference

Named wiring from the pinout research; connector shape alone does not establish capabilities.

Open field note Source trail

Source checked · no independent review claimed · Fabrication approved: no

3-pin PC fan engineering reference original orientation schematic — Original pinout diagram; read the exact variant and view below. Not to scale.

Contact count

Not asserted

Source-scoped connector interface

Mating boundary

Shape is not the verdict.

Check the exact device and mating connector.

Orientation

How to read this profile

Read the exact variant view convention. Schematic layouts do not establish physical positions.

Source-scoped identification facts

Each value retains its exact example, role and measurement axis. Facts from different parts must not be combined into an invented component.

Documented examples; not a mating drawing or compatibility approval
Positions / cavity span	3 (Noctua NF-A8 FLX fan assembly)S835Source-scoped examples are separate; select the exact variant and measured axis. Noctua NF-A8 FLX fan assembly. Named primary-source example only. Identification facts do not certify mating, electrical compatibility, fabrication or powered use.
Contact rows	1 (ASRock H81M CHA_FAN2/PWR_FAN1)S834Current primary-source scoped values; named examples remain separate and unknowns are not inferred from illustrations. Exact equipment variant ASRock H81M CHA_FAN2/PWR_FAN1, manual contact arrangement only; no generic component family geometry. Quantity context: Source manual contact row.
Connector role	3-pin fan cable connector (Noctua NF-A8 FLX fan assembly)S835Source-scoped examples are separate; select the exact variant and measured axis. Noctua NF-A8 FLX fan assembly. Named primary-source example only. Identification facts do not certify mating, electrical compatibility, fabrication or powered use.
Shell / form	Connector type listed as 2510-3PIN (or equal) (Noctua NF-A8 FLX fan assembly)S835Source-scoped examples are separate; select the exact variant and measured axis. Noctua NF-A8 FLX fan assembly. Named primary-source example only. Identification facts do not certify mating, electrical compatibility, fabrication or powered use.
Exact part / implementation	NF-A8 FLX (fan assembly connector implementation) (Noctua NF-A8 FLX fan assembly)S835Source-scoped examples are separate; select the exact variant and measured axis. Noctua NF-A8 FLX fan assembly. Named primary-source example only. Identification facts do not certify mating, electrical compatibility, fabrication or powered use.

Not recorded: Nominal contacts, Populated contacts, Contact pitch, Dimensions / axis, Contact gender / arrangement, Mounting, Coupling / latch, Keying / polarization, Manufacturer, Series, Recorded markings, View convention. Unknown fields stay unknown; illustrations supply no measurements or pin assignments.

Recorded variant and source limits

Check the exact device manual before wiring or applying power.
ASRock H81M 3-pin CPU_FAN2 / CHA_FAN2 / PWR_FAN1 board headers: Diagram labels GND, +12V and FAN_SPEED in order from the end next to the locking ramp; contact numbers are not printed.
Noctua NF-A8 FLX: Numbered fan-cable contacts in the Noctua NF-A8 FLX specification; left/right face and wire-entry orientation remain UNVERIFIED.
Noctua NF-A8 5V: Numbered fan-cable contacts in the Noctua NF-A8 5V specification; left/right face and wire-entry orientation remain UNVERIFIED.

Report a correction to these facts →

Pins & wiring

Pinout

Choose the exact wiring. Pin numbers follow its stated view; a schematic does not establish physical positions. Check your exact device before wiring.

Dark pinout view

What the status labels mean

Confirmed: Recorded research passes agree within this variant; this is not independent human review or hardware validation.
Single source: Only one underlying document, or one pass, supports this assignment.
Device-specific: Supported for the named equipment or wiring only. Check your device’s manual.
Unverified: Missing or conflicting evidence. Do not wire from this row.
Not connected: The source explicitly says NC, no contact or no pin for this wiring.

Wiring variantASRock H81M 3-pin CPU_FAN2 / CHA_FAN2 / PWR_FAN1 board headers

ASRock H81M 3-pin CPU_FAN2 / CHA_FAN2 / PWR_FAN1 board headers

Device-specific wiring. Check your device’s manual before connecting or applying power.

View and evidence limits

Diagram labels GND, +12V and FAN_SPEED in order from the end next to the locking ramp; contact numbers are not printed.

P343 3-pin fan — **Partial**: numbered evidence in B only — A's ASRock H81M diagram labels positions but no numbers, so its three rows stay unverified. B's numbered Noctua NF-A8 FLX and NF-A8 5V specifications give 1 ground, 2 Vcc, 3 RPM. These are named fan-cable variants with different supply voltages, not an independently confirmed universal motherboard map.
The same manual says a 3-pin CPU fan plugged into the 4-pin CPU_FAN1 goes on 'Pin 1-3', but the 4-pin diagram also does not print numbers.
Signal order is shown but contact numbers 1-3 are not printed in the ASRock diagrams, so the number-to-signal mapping is unverified.
Intel's 4-Wire PWM Controlled Fans specification (rev 1.2/1.3) was not found on an Intel host; only third-party mirrors were located and not used. A Noctua white paper on noctua.at was blocked by a bot checkpoint / HTTP 429.

Schematic only · physical contact positions unconfirmed. Original drawing · not to scale. Scroll sideways if needed.

Not yet independently confirmed. No settled pin table is available for this wiring.

Sources (1)

S834 · ASRock · H81M User Manual
Version 1.1, published October 2014 · Section 'Onboard Headers and Connectors', Chassis and Power Fan Connectors (3-pin CHA_FAN2, 3-pin PWR_FAN1) printed p. 25, and CPU Fan Connectors (3-pin CPU_FAN2) printed p. 26

Noctua NF-A8 FLX

Device-specific wiring. Check your device’s manual before connecting or applying power.

View and evidence limits

Numbered fan-cable contacts in the Noctua NF-A8 FLX specification; left/right face and wire-entry orientation remain UNVERIFIED.

P343 3-pin fan — **Partial**: numbered evidence in B only — A's ASRock H81M diagram labels positions but no numbers, so its three rows stay unverified. B's numbered Noctua NF-A8 FLX and NF-A8 5V specifications give 1 ground, 2 Vcc, 3 RPM. These are named fan-cable variants with different supply voltages, not an independently confirmed universal motherboard map.
No separate fourth PWM contact.
Twelve-volt model; do not assume all three-pin fans use the same voltage.
Only named fan cables are mapped. Generic motherboard DC behavior, other voltages/models and a physical face/rear numeric layout are unverified.

Schematic only · physical contact positions unconfirmed. Original drawing · not to scale. Scroll sideways if needed.

Noctua NF-A8 FLX — source-scoped contact map
Pin	Signal	What it does	Status
1	Ground (GND), black	Ground reference and return.	Device-specific Sources
2	Voltage (Vcc), red	Power connection (Voltage (Vcc), red). Check the specified supply.	Device-specific Sources
3	RPM Signal, yellow	Wire colour for this termination: RPM Signal, yellow.	Device-specific Sources

Sources (1)

S835 · Noctua · NF-A8 FLX — Specifications
Undated live manufacturer specification page; accessed 2026-10-21 · Specifications > Extended specifications > Electrical specifications, Rated voltage and Pin configuration rows; Mechanical specifications > Connector type

Noctua NF-A8 5V

Device-specific wiring. Check your device’s manual before connecting or applying power.

View and evidence limits

Numbered fan-cable contacts in the Noctua NF-A8 5V specification; left/right face and wire-entry orientation remain UNVERIFIED.

P343 3-pin fan — **Partial**: numbered evidence in B only — A's ASRock H81M diagram labels positions but no numbers, so its three rows stay unverified. B's numbered Noctua NF-A8 FLX and NF-A8 5V specifications give 1 ground, 2 Vcc, 3 RPM. These are named fan-cable variants with different supply voltages, not an independently confirmed universal motherboard map.
No separate fourth PWM contact.
Noctua explicitly marks the 5 V model as not for use in PCs.
Only named fan cables are mapped. Generic motherboard DC behavior, other voltages/models and a physical face/rear numeric layout are unverified.

Schematic only · physical contact positions unconfirmed. Original drawing · not to scale. Scroll sideways if needed.

Noctua NF-A8 5V — source-scoped contact map
Pin	Signal	What it does	Status
1	Ground (GND), black	Ground reference and return.	Device-specific Sources
2	Voltage (Vcc), red	Power connection (Voltage (Vcc), red). Check the specified supply.	Device-specific Sources
3	RPM Signal, yellow	Wire colour for this termination: RPM Signal, yellow.	Device-specific Sources

Sources (1)

S836 · Noctua · NF-A8 5V — Specifications
Undated live manufacturer specification page; accessed 2026-10-21 · Specifications > Extended specifications > Electrical specifications, Rated voltage and Pin configuration rows; Mechanical specifications > Connector type

Unknowns stay unknown.

Check the exact device manual before wiring or applying power.

Your next step

Use the detail without guessing past its limits.

Read the connector field note Recognition clues and practical checks.Work through a connection Keep exact equipment and cable requirements separate.

Source trail

Claims and sources

C810Dsource checked

ASRock H81M 3-pin CPU_FAN2 / CHA_FAN2 / PWR_FAN1 board headers: original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.

ASRock · H81M User Manual ↗
Section 'Onboard Headers and Connectors', Chassis and Power Fan Connectors (3-pin CHA_FAN2, 3-pin PWR_FAN1) printed p. 25, and CPU Fan Connectors (3-pin CPU_FAN2) printed p. 26 · Source scope and unresolved evidence are preserved in the engineering variant.

C810Esource checked

Noctua NF-A8 FLX: original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.

Noctua · NF-A8 FLX — Specifications ↗
Specifications > Extended specifications > Electrical specifications, Rated voltage and Pin configuration rows; Mechanical specifications > Connector type · Source scope and unresolved evidence are preserved in the engineering variant.

C810Fsource checked

Noctua NF-A8 5V: original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.

Noctua · NF-A8 5V — Specifications ↗
Specifications > Extended specifications > Electrical specifications, Rated voltage and Pin configuration rows; Mechanical specifications > Connector type · Source scope and unresolved evidence are preserved in the engineering variant.

C343Wsource checked

The named ASRock H81M CHA_FAN2 and PWR_FAN1 diagrams show three positions in one inline row. The manual gives no pitch or exact header component part.

3 source records support this profile. No independent engineering review or hardware validation is claimed.

Evidence behind this page

Scope first. Source second. Approval separate.

3 linked sources · 4 scoped claims · 0 sources with inspection/access flags.

Page scope: Original schematic; not to scale and not fabrication approval.

Assessment 2026-10-22 · earliest scheduled source review 2027-01-19. This is a recorded-date assessment, not a live source check. Page-level independent review is not established by this panel.

Inspect 3 source scopes, access limits and dates

S834 · H81M User Manual

ASRock · Unclassified publisher domain · inspected 2026-10-21 · due 2027-01-19

Within inspection window

Scoped support: Exact named pinout variant only; not capability or compatibility approval.

Not established / limitations: Source scope and unresolved evidence are preserved in the engineering variant.

Locator: Section 'Onboard Headers and Connectors', Chassis and Power Fan Connectors (3-pin CHA_FAN2, 3-pin PWR_FAN1) printed p. 25, and CPU Fan Connectors (3-pin CPU_FAN2) printed p. 26

S835 · NF-A8 FLX — Specifications

Noctua · Unclassified publisher domain · inspected 2026-10-21 · due 2027-01-19

Within inspection window

Scoped support: Exact named pinout variant only; not capability or compatibility approval.

Not established / limitations: Source scope and unresolved evidence are preserved in the engineering variant.

Locator: Specifications > Extended specifications > Electrical specifications, Rated voltage and Pin configuration rows; Mechanical specifications > Connector type

S836 · NF-A8 5V — Specifications

Noctua · Unclassified publisher domain · inspected 2026-10-21 · due 2027-01-19

Within inspection window

Scoped support: Exact named pinout variant only; not capability or compatibility approval.

Not established / limitations: Source scope and unresolved evidence are preserved in the engineering variant.

Locator: Specifications > Extended specifications > Electrical specifications, Rated voltage and Pin configuration rows; Mechanical specifications > Connector type

Trace 4 claims to their source records

C343W · P343

The named ASRock H81M CHA_FAN2 and PWR_FAN1 diagrams show three positions in one inline row. The manual gives no pitch or exact header component part.

Claim scope: Exact equipment variant ASRock H81M CHA_FAN2/PWR_FAN1, manual contact arrangement only; no generic component family geometry.

Source links: S834 · Evidence trail → (private workspace)

C810D · P343

ASRock H81M 3-pin CPU_FAN2 / CHA_FAN2 / PWR_FAN1 board headers: original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.

Claim scope: Pinout variant only; see comparison and per-contact status. Not fabrication approval.

Source links: S834 · Evidence trail → (private workspace)

C810E · P343

Noctua NF-A8 FLX: original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.

Claim scope: Pinout variant only; see comparison and per-contact status. Not fabrication approval.

Source links: S835 · Evidence trail → (private workspace)

C810F · P343

Noctua NF-A8 5V: original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.

Claim scope: Pinout variant only; see comparison and per-contact status. Not fabrication approval.

Source links: S836 · Evidence trail → (private workspace)

Prepare this page for review →Read the evidence method →

Recorded evidence only. An inspection date, publisher label, source link or generated packet is not independent technical review, hardware testing, fabrication approval or a compatibility verdict.