It seems to be operating better with minimal work done to it being only blowing out the dust inside and I turned it on the other night for 45 minutes and it did not kick out for me once and speakers were only in the lefts of B and C. I hooked them all in to the left speaker only and it would play sometimes for 5 seconds then cutout, come right back on play for 2 minutes, then repeat, sometimes it would cut out for up to a minute. I just hooked one speaker to A and one to B and they both worked and so did C. It sat on my table for about a week untouched and I happened to flip the switch and heard the tell tale click, so I hooked up a set of speakers to it and it was working. I brought it home and plugged it in and I to experienced the same results. I have a vintage 939 that a coworker has given me because I am considering buying it and when he first powered it up it did not give the click you hear before the sound starts playing.

Now I can quit worrying about my equipment issues & start enjoying the music again! Thanks again to all who responded to this thread.

It feels so good to be in love with my vintage Pioneer receiver all over again. I've had no weird noise issues for a few days now (I can't believe I didn't even think to try this earlier).ДЄt this point, I figure that even if the Speaker B switch goes at some point down the road, I still have a 3rd chance with the Speaker C switch! The SX-1010 has provisions for 3 sets of speakers, so I simply connected my speakers to the Speaker B jacks, & now all appears to be well. Not so, as it turns out that this WAS the problem all along, at least so it seems, so far. A few minutes later, I tried to engage the switch to see if the noise had died down, & the switch wouldn't stay locked into position. Knowing that it would probably die down after half a minute or so, I just disengaged the Speaker A switch, which I had my speakers connected to. The best part is, it's not really a problem at all anymore.ДЄ few days ago, my left speaker was emitting quite a bit of noise as soon as I powered up the SX-1010. Well, I seem to have figured out the problem, & purely by accident. So, get it looked at now is my recommendation. You do hear a click when the receiver comes on, right? DC offset, when bad enough, _should_ cause the speaker protection circuit to kick out the relay. Yes, the unit _should_ have its speaker protection relay operating but that's not going to be good enough. Now, here's the danger you need to conider: If the transistor is at the front end of this powerfull receiver, then as it starts to get worse - and it most likely will - you run the risk of damaging your speaker on that channel. Thermally unstable transistor junctions are well-known culprits here. The fact that the symptoms go away tends to indicate a thermal-related problem. I would tend to doubt the leaky cap theory - at first pass - until I'd eliminated the noisy transistor theory. If this was on my bench, I'd be looking at the signal coming into the power amp board for the channel in question. This would place it close to the power amplifier board. What is being described, here, is most likely a noisy transistor - it will be somewhere after the volume and balance controls.

I've cleaned both the volume & balance controls very thoroughly with contact cleaner, but it hasn't improved the problem at all. In fact, if I turn the volume all the way down AND turn the balance control all the way to the right, I still get the crackling sound coming out of the left speaker! Also, if I turn the volume up while it is producing this noise, it doesn't get any worse. Now here's the weird part: As I said, this crackling noise only comes out of the left speaker, & if I turn the balance control all the way to the right, I still get the static sound coming out of the left speaker. All functions work perfectly & there is nothing wrong with the sound. It usually lasts for about 15-30 seconds, & then peters out to nothing, & everything is fine.

Over the past 2 weeks or so however, I've been getting a fairly loud, erratic, static-like sound coming out of the left speaker ONLY when I power the receiver up. The unit is super-clean & everything was working perfectly. A couple of months ago I bought an old Pioneer SX-1010 receiver off of Ebay.

Kenwood tk 880 clicking sound