Often, a high-resistance or "open" resistor powering the standby IC will cause intermittent starting issues. Main Electrolytic Capacitor:
The top-level schematic of the primary side manages raw AC voltage and steps it down to a high-voltage DC.
A commonly identified issue is the shorting of the MBR3100H (or similar, such as SR310 ) diode located on the output of the standby voltage transformer. This diode can fail due to excessive heat. 4. Pinout and Connector Info ps42419ha schematic top
The AC input enters through a fuse (often 4A) followed by an EMI filter consisting of X/Y capacitors and inductors to reduce noise.
The central chip responsible for the independent standby voltage rail. In many versions of this board, it uses a TNY279PN or similar Power Integrations TinySwitch IC. Often, a high-resistance or "open" resistor powering the
| Symptom | Common Cause | Affected Component Area | | :--- | :--- | :--- | | - No LED, no fan spin, no POST. | Primary side component failure, blown fuse, or failed diode bridge. | Primary Side | | Standby LED On - System fails to start or immediately shuts down. | Secondary side capacitor failure, faulty startup circuit, or compromised IC (e.g., PS25A). | Secondary Side | | Intermittent Boot Loop - System restarts endlessly. | Capacitor aging (Teapo/LTec caps), leading to unstable power delivery. | Secondary Side | | Over-Protection Engagement - PSU shuts down after a brief fan spin. | Short circuit in output, faulty over-voltage protection circuit (OVP), or failing switching MOSFETs. | Secondary Side / Protection Circuitry | | No +5V Standby - Motherboard not receiving standby power. | Fault in the +5VSB generation circuit or standby transformer. | Primary Side |
Understanding the top architecture, standby voltage regulation, and primary failure modes of this circuit layout allows technicians to perform successful, cost-effective board repairs. Technical Overview of the HP PS-4241-9HA PSU This diode can fail due to excessive heat
The term “schematic top” likely refers to a or a component placement map of the PSU’s PCB. While HP does not release full circuit diagrams for proprietary power supplies, several alternative documents can serve the same purpose:
The top schematic always places these high-current paths wide and without switching noise injection points. Decoupling capacitors (typically 10µF to 100µF electrolytic + 0.1µF ceramic) must be placed physically close to these pins.
: Includes a fuse, EMI filter, and a bridge rectifier to convert AC to high-voltage DC.
The primary workhorses of the PSU, powering the CPU, GPU, and drives.