Now That's More Like It
The 24V rail looks considerably better. Ripples are reduced from a wildly fluctuating 600-1000mVPP to a steady 200mVPP, even without super-sizing (and despite the Epcos having a 100kHz impedance of 27mΩ vs. 18mΩ for Samwha).
Out of curiosity, I tried measuring the old 35V caps and neither of my meters were able to take a reading due to excessive leakage current. Those two capacitors were definitely well past their prime.
Both my multimeter and DIY current probe agree that the monitor draws 43mARMS on standy at 117.6VRMS line voltage, yielding an apparent power of 5.5VA. The part of the current waveform that is leading by nearly 90° is the power input EMI filter's capacitors, while the small 150mA bumps are from the input cap getting topped off at AC peaks. Those peaks are enough to reduce the lead to 61° and bring the power factor up to 0.49. The off-scale glitches (about 300mA peak) are runt pulses from the APFC when it initially detects the top-off current.
Once distortion power (everything that is not 60Hz including noise) and reactive power are subtracted, the net standby power is 1.7W.
With the display turned on, the APFC controller kicks in and the current waveform tracks the voltage waveform closely whenever the line input is above 50V. The input current is 504mARMS leading by 7° at 117.1VRMS for 59VA with a power factor of 0.99, which is practically perfect.
After removing what little distortion and reactive power is in here, we are left with 57W net power. This is with the monitor on its “no signal” screen and 40% brightness. I wonder how much of a difference my repair might have made, but I did not think of measuring power and PFC before the switch.
Replacing caps is just about the simplest and cheapest electronics repair you can possibly perform, next to replacing fuses in an otherwise working circuit (at least when the fuse is not internal and soldered to the PCB, as is the case here).
What really bothers me is how so many consumer electronics manufacturers appear to be using caps that barely outlive the warranty when they could get considerably better ones, preferably not discontinued for the better part of a decade, for a few extra pennies. Things like this make me wish governments would bump the minimum legal warranty to three years to reduce the amount of e-waste generated by what appears to be engineered failure. Aside from the output caps, everything else inside the monitor still looks good as new.
I hope you enjoyed this different tear-down! If you want more, leave suggestions in the comments below.