Ps42419ha Schematic Work

Failure in the switching MOSFETs or the PWM controller IC.

Locate the "Startup Circuit" on the schematic. Usually, you will find 2 to 4 high-value resistors (220kΩ to 1MΩ) in series connecting the bulk capacitor voltage pin to the VCC pin of the PWM controller.

: The unit is 80 PLUS Gold certified , achieving a typical efficiency of 90.51% at 50% load. Technical Specifications Specification Rated Output Power Input Voltage 100V – 240V AC Typical Efficiency 90.51% (at 50% load) Form Factor Custom (Specific to HP Compaq series) Common Uses & Replacement ps42419ha schematic work

What is the computer showing? (No power, blinking light, clicking noise) What voltages have you measured on the output pins?

Look for burnt components, bulging capacitors, or damaged PCB traces. Failure in the switching MOSFETs or the PWM controller IC

Large electrolytic capacitors on the high-voltage side can fail or exhibit high ESR (Equivalent Series Resistance), leading to fluctuating output or startup failure.

If the green wire registers an open-circuit voltage of roughly ~4.3V to 5V, but bridging it to ground yields no output from the main rail, the primary bulk section or supervisor loop is faulted. : The unit is 80 PLUS Gold certified

The moment of truth came with the "paperclip test." Connecting the green wire to the black (ground) on the ATX connector, the fan spun to life. A steady 12.2V appeared on the meter. The "clicking ghost" was gone, and the PS-4241-9HA returned to service, proving that with a solid schematic and a little patience, even "obsolete" hardware can find a second life. Key Technical Specs for the PS42419HA

The secondary circuit splits into designated lines to supply main system power. This includes +12V1positive 12 cap V sub 1 +12V2positive 12 cap V sub 2 , and a minor -12Vnegative 12 cap V

To diagnose the power supply without the computer, you need to simulate a "power-on" signal. On most standard PSUs, this is done by shorting the PS-ON signal to ground. However, the PS-4241-9HA uses a proprietary 6-pin connector with a specific pinout. A common documented workaround to force the unit on is to locate and bridge the "FPO" (likely "Fault Power Off" or similar) pin to ground.