Onkyo TX-NR828 - popping sound every 5 min

[roman-hartwig]

Object: Onkyo TX-NR828
Problem: Popping noises in the right surround channel every ~5min
Service manual: available

After I was able to bring my beloved Onkyo back to life (total failure of the power amplifiers) and it has now been doing its job for some time without any problems, it is now ailing with a new problem. It still works fully, but after about 5min it "pops" in the right surround speaker for about 0.5 sec very loud (100% volume). I am almost scared to death - sounded like a battery exploding or something. It sounds like something is discharging - a capacitor? However, the channel works "without" problems - so it continues to output sound cleanly, apart from the described phenomenon.

Does anyone have an approach or an idea what the problem could be?

Thanks in advance.


P.S.: I linked pictures and service manual in the previous thread about power amp repair => https://www.badcaps.net/forum/showthread.php?t=118047

[petehall347]

Re: Onkyo TX-NR828 - popping sound every 5 min

bad transistors can cause that

[roman-hartwig]

Re: Onkyo TX-NR828 - popping sound every 5 min

When you talk about a "bad transistor", do you have a specific one in mind? Because basically the channel is still giving a clean sound, it's just that it's making cyclic pops. Wouldn't a bad transistor prevent the channel from working at all?

[petehall347]

Re: Onkyo TX-NR828 - popping sound every 5 min

https://audiokarma.org/forums/index..../post-11692536

[roman-hartwig]

Re: Onkyo TX-NR828 - popping sound every 5 min

The phenomenon I described is more of a "bang" and occurs about every 5 minutes. So it is louder and more abrupt. Ok, let's assume it's a similar problem, then the fault is in one of the transistors shown in the attached picture? I imagine a diagnosis with cold spray as in the linked article difficult, since it is not present all the time. Would such a transistor have to have measurable variances to identify it, or does one in the schematic catch your eye directly? And thanks already for the hint.

[petehall347]

Re: Onkyo TX-NR828 - popping sound every 5 min

i dont see any known to go noisy transistors .
i would give the freeze spray a try to see what happens , gentle heat also finds things sometimes .

[roman-hartwig]

Re: Onkyo TX-NR828 - popping sound every 5 min

OK, I will try and get back to you, hopefully with progress