4 pin HP video power connector.
This proprietary 4-pin internal header was fitted to certain late-1990s HP Pavilion desktop systems that included an EnSoniq soundcard (typically the ES1370 or ES1371 chipset). Despite being labelled “video power” in early community documentation, the connector supplies ±12 V to the onboard power amplifier of the soundcard, not to any video circuitry. No public HP service manual or industry standard governs this pinout; the assignment was established through community reverse-engineering of affected Pavilion models produced approximately 1997–1999. The voltage arrangement — −12 V on pin 1 and +12 V on pin 4 with separate ground returns on pins 2 and 3 — broadly mirrors the structure of the ATX floppy drive power connector, but uses a bipolar ±12 V supply rather than the ATX’s +5 V/+12 V combination.
| Pin | Name | Direction | Description |
|---|---|---|---|
| 1 | -12 Volts | IN | -12 Volts |
| 2 | Ground | - | -12 Volts Ground |
| 3 | Ground | - | +12 Volts Ground |
| 4 | +12 Volts | IN | +12 Volts |
Signals
- -12 Volts — negative 12 V rail supplying the inverting supply rail of the audio power amplifier
- Ground (pin 2) — return path for the −12 V rail
- Ground (pin 3) — return path for the +12 V rail
- +12 Volts — positive 12 V rail supplying the non-inverting supply rail of the audio power amplifier
Notes
This header is a platform-specific implementation found only in select HP Pavilion models of the late 1990s. It is not part of any ATX, ATX12V, or other industry power supply standard. The connector physically resembles smaller proprietary headers of the era; it should not be confused with the standard ATX 4-pin peripheral (Molex) power connector, which operates on +12 V and +5 V at 5.08 mm pitch, nor with the ATX floppy drive connector (2.5 mm pitch, +5 V and +12 V). The bipolar ±12 V supply is required by the audio amplifier stage and must not be substituted with a unipolar source.
References
- ATX Version 3.0 Multi Rail Desktop Platform Power Supply Design Guide v2.01 — Peripheral Connectors — Intel Corporation (for ATX standard context)
- ATX 12V Power Supply Design Guide v1.3 (Internet Archive) — Intel Corporation