Yamaha RXV-2600 capacitor issue - bulky fix

[HendriXML]

Hi,

5 years ago I repaired my Yamaha receiver with the famous C4 22 nF capacitor replacement. Comparable to this:
https://youtu.be/MwvjAtSr5t8

However the first signs are showing it's faulty again. Some person on the net mentions it should be replaced by a X2 rated dielectric capacitor.
I went searching for those on some old pcb-s and found some. But most off them are a fraction of their spec.

This raises the question what is better a new one that will drop, or an old one that has already dropped, but has reached now 30 nF. (A bit too high?)

Maybe there's some type of capacitor doesn't need replacing that often?

[aqibi2000]

5 years is a good life

Out of the usual 20% spec

[andy2000]

I generally consider film caps like that to be lifetime caps.  They rarely fail unless abused.  Clearly that cap isn't right for the application.  I would probably try a higher voltage part.

[mzacharias]

The RX-V2600 is nothing like the receiver shown in the YouTube video;

That cap is not present, and is not the problem.

You did not even mention the problem you are having with the 2600; however I will mention they did have a problem with the electrolytic capacitors in the low-pass filter portion

of the feedback loop on these. 47uF or 100uF (I forget which) associated with the differential pair for each amp circuit. The DC offset may wander around or go full high,

triggering the protection circuit.

[HendriXML]

The RX-V2600 is nothing like the receiver shown in the YouTube video;

That cap is not present, and is not the problem.

You did not even mention the problem you are having with the 2600; however I will mention they did have a problem with the electrolytic capacitors in the low-pass filter portion

of the feedback loop on these. 47uF or 100uF (I forget which) associated with the differential pair for each amp circuit. The DC offset may wander around or go full high,

triggering the protection circuit.

Hi Mzacharias,

From browsing the forum before posting this one, I saw you're knowledgable about repairing Yamaha's. I didn't mention the symptoms because the problem was already diagnosed. I had the same problem 5 years ago. And fixed it using the links posted below. Later I became more interested in electronics and saw Dave's video with a similar problem.

Maybe you can advise a cap which result in a more durable fix? It is an easy fix but it takes quite some time to get access to the receiver.




https://www.diyaudio.com/forums/solid-state/226279-yamaha-rx-v2600-power.html

https://www.avforums.com/threads/yamaha-rxv1700-power-problem.1533016/

[HendriXML]

In the service manual C4 is mentioned multiple times in the part list, does this mean it can be replaced with the best pick of those?

[HendriXML]

I generally consider film caps like that to be lifetime caps.  They rarely fail unless abused.  Clearly that cap isn't right for the application.  I would probably try a higher voltage part.

Looking at the list in my previous post, this might also be what the service manual suggest. Replacing it with a 630V one, and also higher capacitance.
I guess it has to be a safety capacitor?

I took an image of the best match I could find on some PCB. It's capacity has dropped to 30 nF. It voltage is on the low side, but I guess OK.

[HendriXML]

In the service manual C4 is mentioned multiple times in the part list, does this mean it can be replaced with the best pick of those?

There's an extra column not shown which shows for which country which capacitor spec is ment, so mine can only be replaced by a 22 nF. Quite logical because it kind of drops mains voltage.
So I won't be using the desoldered one.

[HendriXML]

Because it would be the second repair of the same problem I wanted a better fix. As mentioned in this thread one with a higher voltage rating might be better. I decided to go with 1,5/2,5 kV from a crt tv. The ones it had where 8,2 nF. Having both in parallel means it gets to 16.4 nF. But because the faulty one was only 7 nF, and probably was just over the edge of resulting in failing I think they're good enough. I measured quite a few film capacitors and a lot of them where only a fraction of their intended spec. Hence the idea of taking high quality ones which were stil spot on, even after being in use.
They're a bit heavy so I drilled 2 holes for some tie wrap. Space enough  .
After this fix the receiver works as expected. The idea is now that those over dimensioned ones won't drop in capacitance.