Recapping a Denon AVR X6400h SMPS

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(TLDR: It was capacitor C6519 [Koshin KZH 50V22uF] and C6515 [Koshin KZH 25V47uF] on the power supply. I have questions at the end)
Disclaimer: I'm an amateur hobbyist and will get things wrong.
Always use caution when working around mains power and high voltage capacitors!
Hey guys, I'm repairing a Denon AVR X6400h for my brother. It quit powering on after a power outage. It acted like this last time there was an outage, but after letting it sit overnight it started working again for a few years. This time letting it sit did not bring it back.
SYMPTOMS:
-No display
-The relay on the power supply would click on then off immediately. And only occasionally and randomly. Most of the time it didn't activate at all.
-Just a very dim, red flashing power/standby light.
-At connector N6513 on the power supply, voltage would jump to 5.2v, then taper off to about 4.3v, the pop back up to 5.2v, then taper back down. This voltage peaking and tapering happened even if the SMPS was completely disconnected from the system.
- If I pressed the power button while the red flashing light was lit, the light would then start flashing white, but the unit never powered on.

At first I thought the flashing red light was an error code, but now I think it was the power supply turning on and off. The first time I removed C6519 and C6515 and tested them in an ESR02 Pro, the capacitance was close to spec, and the ESR was pretty close to the chart on the back. Note that these are Koshin KZH series ultra-low impedance caps, so they were probably already outta spec. I'm an amateur and didn't realize they were bad yet. I reinstalled them, but I was still suspicious there was Bad Caps(.net)
I removed the power supply and connected my multimeter in DC volts mode to the output. Then i plugged in AC power and blew hot air onto the suspicious capacitors one by one until, viola! The voltage jumped to the expected output of 5.2v and stabilized. After about 30 seconds the caps had cooled and the voltage went back to peaking and tapering. Blow more heat and get stable voltage. After a few tests I isolated the problem caps back to C6519 and likely C6515. When I took the caps back out and ran them in the ESR02 Pro again, the capacitance was still very close, but the ESR was much higher now. C6519 was showing 4ohms ESR, and C6515 was showing 2.1ohms ESR. So I'm ordering replacement capacitors, Panasonic FR series in the same specs.
Should I also replace C6525, C6526, and C6527? They are ELNA RJM 10v3900uF and two 10v1500uF. They are the three capacitors on the low-voltage side of the Power Supply. Will add pics soon!

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She's quite the unit with 11 channels.



Bad caps circled in red (C6519, C6515). Should I replace the blue ones too?




Power Supply Part number: 8U-110207-7 . At least she's got one Ruby.



The baddies.

[CapLeaker]

No surprise there. Small caps next to a heat sink are always trouble. One of my first things I look for. Unless the other once circled in blue are 40 years old, they are still going to be within tolerance. Take em out and check.

[CapLeaker]

… forgot to mention: never test a hot capacitor. The ESR and capacitance reading will be off. That’s why the blow hot air on bad caps trick works to start a PSU for example,

[Green Probe]

Thanks for the tips! Maybe I didn't wait long enough for them to cool down the first time I tested them. I do take a minute to clean the flux off the legs with alcohol before putting them in the ESR meter. I'll definitely check the blue circled caps this evening. Do you think I should check the 400v Rubycon capacitor because it's also near the heatsink? If so, do you have any tips on getting the glue to free up? I tried alcohol, but it seemed immune. Also, how do I know what ESR value to expect? Should I use the reference chart on the backside of the ESR02 Pro; or should I use the 100kHz impedance value on the capacitor's datasheet? Thanks again!

[CapLeaker]

To really test a high voltage capacitor you need something else than an ESR meter. On these you actually need to do a leakage test to be sure.
I’ e run into this before. Some high voltage caps show good one of the most expensive Fluke meter and a ESR component tester. But somehow there is still a problem. So I did take them out for a leakage test and then they all had failed.

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I may just leave the big Rubicon cap alone then, considering its glued down. The glue is pretty hard, and I'd hate to damage the PCB. For the small low-ESR caps, should I use the chart on the backside of the ESR meter, or reference the datasheet? Or is there another way to tell what's 'in spec' for a particular cap? Thanks for all the info!

I ordered Panasonic FR's to replace the ELNA RJM caps circled in blue, but I since realized the FR's ripple current rating is a bit lower. If the ELNAS turn out to be bad I suppose I'll get some Nichicons. I didnt see a 10v 3900uf Rubycon with low impedance on Mouser.

[CapLeaker]

Then take the next voltage and or capacitance range up. There is a 10% rating on caps anyway.
Example: If you replace a 10V 680uF with a 16V 680uF or a 16v 1000uf that should work fine as kind. I don’t have every voltage range capacitor either.in stock.

[Green Probe]

Good point. The next size up would have been a good choice. Does TopCat or anyone else still sell caps on here? The store page URL is broken.