Pioneer VSX-1016 Noise During Test Tones

[mmartell]

Sound seems clean during normal playback but when I run the test tones there is a noise in all channels that aren't being tested. The noise can be increased with the volume control and goes away when I exit the test tone.

Any ideas ?

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

Is there a way to isolate this ? I can't be sure whether the noise is actually there during radio playback because the signal is shitty to start with but with any other input I hear nothing - but maybe the signal is internally muted with no input..

Need some help with this.

[Longbow]

Re: Pioneer VSX-1016 Noise During Test Tones

This has the earmarks of a DSP failure. It might be possible to isolate the problem further with block diagrams and schematics (are those available?). But, why would all channels get noisy at the same time? Your test proves that the amps are not at fault. A check at the D/A converter should show the noise. These are generally tough problems to pin down. Run any software updates first, however.

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

Yes I have the SM for this though it's a bit above my head on how to interpret it. I have a dmm and a scope if you can suggest how/where to take some measurements.

I will heat the dsp ic to see if the symptoms change.

I tried attatching the service manual but it failed. It's available at ElektroTanya.

[Longbow]

Re: Pioneer VSX-1016 Noise During Test Tones

Sorry, I don't have access to Elecro-T. If possible, posting just the block diagram would be a good start. Heating and cooling the DSP might give you a clue if the noise changes in some way (use headphones at a low volume levels). Describe the noise - constant, white noise, similar to radio static, etc. Operation normal with various inputs? Be sure to check the various modes (theater, room, etc.) and note any problems. Also many of these units offer a test mode with random noise for setting up room acoustics. Time for the owner's manual!

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

Will post block diagram shortly...

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

Block diagram

[tibimakai]

Re: Pioneer VSX-1016 Noise During Test Tones

You can download two SMs per day, without logging in.

[Agent24]

Re: Pioneer VSX-1016 Noise During Test Tones

I agree with Longbow - are you certain it's not supposed to do that?
It wouldn't be the first time a 'feature' looked like fault.

[kaboom]

Re: Pioneer VSX-1016 Noise During Test Tones

Check/clean/tighten/resolder grounds for DSP.

Use external signal source, either sig gen or CD with test tones.

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

I agree with Longbow - are you certain it's not supposed to do that?
It wouldn't be the first time a 'feature' looked like fault.

No. Right now I only have two speakers hooked up to it and no subwoofer. If I run the test tones for three channels (couldn't see where to tell it there is no sub) then when the test tone is in the right channel I can hear noise in the left and vice versa. When the sub test tone is played I can CLEARLY hear this noise through the left and right speakers.

The noise sounds like part noise, part interference.

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

Check/clean/tighten/resolder grounds for DSP.

Use external signal source, either sig gen or CD with test tones.

Though this is sound advice if this was the nature of the problem would it not be evident on other signals using the DSP ?

[Agent24]

Re: Pioneer VSX-1016 Noise During Test Tones

No. Right now I only have two speakers hooked up to it and no subwoofer. If I run the test tones for three channels (couldn't see where to tell it there is no sub) then when the test tone is in the right channel I can hear noise in the left and vice versa. When the sub test tone is played I can CLEARLY hear this noise through the left and right speakers.

The noise sounds like part noise, part interference.

What kind of signal is the test tone? I wonder if there is some marginal fault which means it can handle normal music etc but not the test tone.

What if you generate a copy of the test tone with your PC in software or signal generator and feed that into the inputs, see if you get the same problem?

Probably not too relevant, but all I can think of - I recently fixed a Roland KR3500 Digital Piano that had a digital noise problem in the left channel. Turned out the DAC for that channel had an open circuit resistor in the voltage divider which adjusted a voltage to change the DAC's MSB offset.
(And yes, it had the known leaking SMD electrolytics problem as well!)

*Maybe* you have a similar problem with a voltage reference being off somewhere?
Note that in the case of my KR3500, it only took a tiny 13mV drop in that voltage to confuse the DAC!

[Longbow]

Re: Pioneer VSX-1016 Noise During Test Tones

Thanks for the block diagram. I think the DSP section of the receiver is missing - that's what you want to focus on - section G. The problem you describe seems abnormal, since a noise test mode would surely be noted, but we do need to check the O.M. first. Also, perform the f.w. update. You DO need the remote on these things to get anywhere.

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

I had a few minutes and so endeavoured to remove the dsp board for close inspection but after removing a few screws and ribbons could not readily see how to extract it. After reassembly the noise is gone, or at least greatly reduced.

Will put the lid back on and see how it holds up under operational stress.

[Agent24]

Re: Pioneer VSX-1016 Noise During Test Tones

Bad solder joints?

[mmartell]

Re: Pioneer VSX-1016 Noise During Test Tones

Could still be that though I couldn't make the noise go away using the butt end of a screwdriver on and around that board. I know, hardly scientific lol. Ran it several hours yesterday and still holding up.