System components:
Onkyo 797 for HT, Sony 300 CD changer, ancient Panasonic VCR, Panasonic RP91 Progressive Scan DVD, Motorola Digital Cable with HD decoder, PL2, Onkyo 8511 used for powering distributed audio, thus utilizing multi source feature of the 797. Monster Cable AV800 surge protection. Oh, Sony T.V- XBR 36".
Problem:
Static, popping type of a sound. It's a distinct pop and it's crazy but the pattern of the "popping" sounds like Morris Code. (That's the first thing I thought when I heard this sound, the client even made the same comment.) Now what's interesting is during any multi channel DSP mode the popping primarily comes from the front right speaker or the center channel. The exception is "Theater Dimesional" and then the popping comes from the front left speaker.Mono movie and teh popping is at the center channel. If the volume is raised considerably then faint popping sounds can be heard from other channels. Now, if I skip the DSP's and go DIRECT, then there is no popping at all. By the way there is no popping in Dist. audio system. The 797 has been installed for 3 months with no problems, and now this. Also this popping occurs with all inputs, analog or digital, and with all other components on or off and during playback. One other thing is the client claims that after 8 minutes exactly the popping would stop. Last night during my visit it never did completely stop but the popping did seem to become more faint. Granted I was constantly switching inputs and DSP's and anything else I could, for about 25 minutes. Hope this is enough info to help troubleshooting.
My conclusion is that the *&^%(processors or crossovers or both) is bad and I need a new unit. But I know that static electricity is a strange thing so I don't want to jump to conclusions. I'll be on the phone with Onkyo ASAP but would like some real world tech support. I'll be sure and post Onkyo's feedback.
So whataya think?
Many thanks,
CMack

If the popping moves around when you change surround modes, the popping is occurring inside of or upstream of the surround processor (May be restating the obvious, but troubleshooting is a process of elimination....) The fact that the popping comes and goes on a regular basis seems to indicate that the noise comes from something that runs on a periodic basis; humidifier, sump pump, the neighbor's vibrating bed, something. It's my guess that the problem is not "in" the processor, but might be a sensitivity to external noise pickup in that Onkyo unit; replacing the unit probably won't help, but changing to a different brand might.
I'm suspicious of the Motorola cable box. Does unpluggin that unit eliminate the periodic noise? Enquiring minds want to know.....

Here's what I would do. I would check the items that are common through all devices: AC and the cable feed.
DIsconnect the cable feed from the wall and see if it goes away. If so, use a ground breaker...a good one like tributaries. If not that, diconnect the monster AC (which I've never had good luck with) and put in a cheap-o power strip, just for testing. If it went away, try a better line conditioner : Furman, Tice, even a Rotel or Adcom.

I have had similar problems with sony equipment but found it not to be the amp but usually a vcr or dvd, the cable box would be a good start.I find most of the time it is something that is back feed from one of these units. Try disconecting equipment one by one, see if it goes away.

Let me know what you find.
Jeff

I've heard of this problem and it's normally assocciated with a DVD player. Are you connected optically or with a coaxial cable?

My vote is the DSP chip in the 797.
The very first run of the Kenwood Soveriegn receivers came with a "prototype" DSP chip that shut off after two hours. Running stereo bypasses the DSP, which is also why your distributed audio does not pop. -Brian.

Havn't been back to the job yet, I'll be there today. I'm connected to the DVD player via optical cable.Running stereo bypasses the DSP,
The popping is present in stereo as well. It only goes away in Mono and DIRECT. I'll have some good info this evening and I'll diagnos everything mentioned above. We'll see.
Thanks,
CMack

The one thing that puzzles me is, that this sound goes away after 8 minutes exactly ( according to the client ). In my opinion that would eliminate the possibility of feed back through the AC. and point towad the DSP chip.
As mentioned I'll find out today.

Is there another device (such as a quick-load VCR) that powers up, and then goes into some sort of sleep/standby type of mode after 8 min. of inactivity? If the timing is accurate and consistent, it's more likely that the source is external to the sound system, unless it's a thermal problem. Will cooling the amp (or other component) change the timing?

Again you must use a process of elimination. Try unpluggind other components one at a time (to be able to identify which step works) or unplug everything (else) and re-connect on at a time. You may have to mess with interconnects as well as power plugs.

You might also see if the homeowner performs some behavior out of rote (habit) that may coincide with the noise. Do they operate the HVAC or start the coffee maker just before turning on the system? I've had systems pop (loud) when electrical contacts open in another part of the house.

Larry
www.fineelectricco.com

i had the same thing with a 797 i got a new one it's works fine

Well I've returned with boring news. It's the 797.
After diagnosing every possibility with no change, I called my rep and yes this is a problem Onkyo has experienced with one batch ( supposedly ) of 797's. FYI, I purchased this unit Jan 19th 2002. It's a little older than I remembered when first posting this thread.
glo153,
Did your unit date with this one I've had problems with?
Thanks for the help.
CMack