When the motherboard pulls the PS_ON line to ground, the main PWM controller activates.
PS-4241-9HA is a high-efficiency 240-watt power supply unit (PSU) manufactured for Hewlett-Packard (HP)
For detailed visual identification of components, you can refer to the HP PS-4241-9HA Verification Report or technical teardowns on platforms like Scribd .
or a faulty resistor powering that IC. Technicians sometimes replace these with slightly higher wattage versions (e.g., replacing an 18W IC with a 20W version) to improve durability. Short-Circuit Protection:
When the computer user presses the chassis power button, the motherboard grounds the line. This alerts the primary supervisor IC to activate the main pulse-width modulation (PWM) engine. ps42419ha schematic work
Input fuse, bridge rectifier, and standby PWM IC.
Ensure the motherboard is pulling the PS_ON pin to the correct logic level (usually grounding it) to wake the power supply from standby.
The PFC circuit switches on, boosting the main filter capacitor voltage from roughly 300V DC to .
It also carries several interchangeable OEM part numbers: . When the motherboard pulls the PS_ON line to
Boosts the rectified voltage to approximately 380V–400V DC. This ensures high efficiency and a power factor close to 1.0. 3. Main Switching and Isolation (PWM Stage)
Based on a visual analysis of the PSU's wiring, the main connector configuration is as follows:
Leo leaned back and smiled. No schematic. No internet. Just patience, a probe, and the ghost of a dead engineer’s design logic. He sent Mrs. Aoki a photo of the repaired board via her café’s Instagram. She replied with a single cat emoji and the thumbs-up.
Large electrolytic capacitors on the high-voltage side can fail or exhibit high ESR (Equivalent Series Resistance), leading to fluctuating output or startup failure. Input fuse, bridge rectifier, and standby PWM IC
If you are performing "schematic work" for troubleshooting (e.g., missing standby voltage), specialized repair videos often reverse-engineer sections of the board:
This is the most frequent issue where the PC fails to power on at all. Troubleshooting usually starts with checking the standby voltage.
A dedicated monitoring chip constantly tracks the lines for unsafe states, triggering an immediate shutdown if thresholds are crossed: OVP / UVP: Over-Voltage and Under-Voltage Protection. OCP / SCP: Over-Current and Short-Circuit Protection. Troubleshooting Common Component Failures
: Alternating current (AC) enters through the plug. A fuse protects the board from power surges. Filters clean up electrical noise so the power is smooth.