"Grass Valley fiber cards had +15 -15 V power supplies where the 220uf axial caps checked good for ESR with the Bob Parker meter in circuit but were faulty. "

this can happen if there arew good caps in parallel with the one under test.. Like the supply itself might have a 220uF, but there could be a bunch of 1 uFs across the vcc/Vdd of a few ICs which will make it read good in circuit.

Same with banks of lytics. i have found that on many powwer supplies you oly have to bridge one in a bank to test the unit. this is from the TV days when we got in a TV that is dead, to put a bunch of caps in the PS oly to find it has screen or Tco problems and is not worth repairing. So I started just taking out one and putting one cap in its place, and I didn't even cut the leads, I let it stand up. I had a stash of caps at the bench for this purpose and saved some money, which of course was part of my job, we weren't wasting a bunch of caps anymore. Once you cut the leads it is alot harder to install on a sometimes overcrowded PC board.

Same thing applies to computer motherboards. just one will get it to work. They use alot of them because of ESR, ESL and ripple current. they might have five of them in there adding up to 10,000 uF, but a single 1,000 will get it working temporarily. One time I did that and it turns out the problem corrupted the BIOS and the system did "hang permanently" in the lingo of the manufacturer.

Everything is so cheap now servicing is all about saving money. People don't care because you can get a new one so cheap, and they don't care that the quality is even worse. Some do, or are comfortable with their old equipment. People who finally learned the whole menu on their TV or whatever, or have older high end stereo equipment. Even then you can't waste money without good reason. Some people want ten buck caps and all thin film resistors in the audio path, change them all. But they are willing to pay, the average sheeple is not.

And those cap values in uF are not that critical. And contrary to popular belief it is NOT good to up the voltage rating. the parameter that really matter are theesr and ripple current cpacity. You really think am SMPS running at 100 KHz needs 10,000 uF worht of filtering ? ****, 10 uF will do it if it can handle the ripple current and has low ESR. and the two go hand in hand. higher ESR causes an AC voltage drop which produces heat by actual power dissipation in the cap. That destroys it prematurely. they got it timed so it lasts through the warranty, and they hope not much longer. Only a few companies build everything so if you need to buy a new one they benefit anyway.

That is one of the main reasons I do not fix TVs anymore. Actually most newer equipment, **** it. Built cheap and specifically hard to service. I got tired of fighting it. And they are winning beause they REALLY control the parts ow. You can get two TVs the same model and there could be five different variations on the chassis, and almost none of the parts are interchangeable. And then there is alot of software and firmware that gets corrupted, and bad caps can cause that.