JayTs :
For anyone who wants to try this type of repair, you need to know the following specs of each capacitor:
1. Capacitance (microfarads or uF). Match or exceed the original.
2. Rated voltage. Match or exceed the original.
3. Diameter and length. You may use a different size if you are sure it will fit.
4. Lead spacing. Measure the distance between the leads from the cap or holes in the PCB.
As explained in the article, capacitors in the power supply should be chosen to handle high ripple current and/or low ESD as necessary.
Well...
1. depending on how the PWM controller is designed, excessive super-sizing could cause control loop stability or transient response issues. The extra energy available in the output caps also means the PWM's output current limit will be less effective at preventing loads from destroying themselves in case of a momentary malfunction or short. Bigger is not always better. I used the super-sized caps I used mainly because I happened to have them in stock and they physically fit on the PCB. Going one or two ratings up rarely hurts but it might not always work, especially with modern devices that require much faster transient response, ex.: Haswell-ready PSUs and VRMs, CPUs, GPUs and SoCs with dynamic core voltage and fast power state changes.
2. that depends on whether the existing caps are used anywhere near their rated voltage. In the LG display here, LG used 25V caps on the 12V rail. I used 16V caps since that is already a 33% margin and should be comfortable enough.
3/4. yup, physical fit is always a make-or-break thing - doesn't matter how good your replacement is if it does not fit.
5. I think you meant ESR, ESL or ESZ. As noted in my tear-down though, reducing ESR may increase ringing since it reduces damping, namely that of resonance between the cap's ESL and other circuit capacitances.
As for how long the LCDs will work with good caps, I think my older LG is about 10 years old now, so my repair extended its life by six or seven years. The CCFLs or the inverter started dying out a few years ago (flickers for a while until it warms up) and I have not looked into that yet. I did have a quick check for any obvious issues but did not find anything. Now that I have an oscilloscope, I could re-open it to at least check voltage rails. If I had a high voltage (3kV) probe, I could also take a look at CCFL voltage, see if the flicker is due to a lamp ignition or inverter output voltage issue. In any case, it seems seven years or so would be a reasonable expectation for CCFL-based LCDs.