Problem with receiver marantz sr5400ose

[stereophonicfan]

For my HT-setup I use my old front speakers Jamo 7.7's (D590) and bought myself a Jamo center (D4cen) and Jamo concert's (D8sur) to complete the system.
This system is driven by a Marantz SR5400OSE.

I have a serious problem with the receiver. About halfway a movie, nearly any movie; from actionpacked to romantic mood, the receiver shuts down and restarts automatically. It's striking that the problem occurs every time after playing about an hour. I first thought of a short-circuit, but if it is a short-circuit why would it restart immediately? Then I thought the receiver was overheated, but there was no exceptional heat coming from the receiver and the receiver simply restarts to soon after shutting down.
When the receiver shuts down there are NO anomalies in sound, no cracks, no bumps, clicks or any other sounds. The receiver simply shuts down and the sounds stops (doens't slowly fade away) then it restarts and play normal for the remainder of the movie.

Does anybody have the same problem or can somebody point out the problem to me?
Something for the audio-wizz on this forum as already brought it to the shop where they don't seem to be able to find the source of the problem and require further testing.

Ever so gratefull Stereophonicfan
(as you can imagine I'm a novice when it come to HT!)

[N. Abstentia]

Well if you take the receiver somewhere else and it works fine, I'd look at two things:

1) Your speakers. Maybe you have a bad one, or maybe they are a lower impedance than your receiver can handle. Check the impedance load on the speakers and see if your receiver is rated to handle it.

2) Power. Make sure you have plenty of clean juice going to the receiver.

[F1]

Your speaker (D590) is rated at 4ohm while your receiver is rated to handle up (down) to nominal 6 ohm. Normally it should not be a problem as long as you don't play it very loud. However, since you said the problem also occurred on every movie I guess there is a problem with the receiver. Try to reset the receiver hopefully it's just a software glitch; check the manual on how to do it. Or see if it helps to set the front speaker to "SMALL" to reduce the load on receiver. You will lose bass output with this setting though and subwofer is needed. Or is it possible to exchange the receiver?

[Slosh]

I have an SR-5200 in my bedroom system and it loses sync for a second on layer changes or if you go from PCM to DTS, etc. The way around this is to shut off the automatic format detection and keep it in the disc's native codec at the start of the movie. Of course if you go from a Dolby Digital DVD to a DTS disc, you'll have to remember to switch sound modes manually.

I doubt it's your speakers. I have some old 4 ohm nominal Missions that I'm running full-range and it has never shut the amp down.

[Woochifer]

As others have asked, are you sure the whole receiver shuts down or is it just a momentary interruption in the signal? Typically when a receiver goes into protection mode because of a potentially damaging load, it locks the unit down and you have to manually reset it. Interruptions in the audio signal are more common, and most often occur when a DVD is in the middle of a layer transition.

If the whole receiver is shutting off, try it out with just the front L/R speakers active, and see if it does the same thing. If all five of your speakers have a nominal impedance of 4 ohms, then that might present a load that the receiver was not designed to handle. Even if a receiver does not post an output rating at 4 ohms, most of the ones out there should be able to handle two 4 ohm speakers at least up to moderate levels. But, once you increase the load by adding low impedance center and surround speakers, then you're going beyond what most receivers were designed for. If you receiver does not shut down whenever you use only two speakers, then the additional load of the center and surround speakers are at issue. You might need to add an outboard amp to drive the main speakers, or try replacing the surrounds with 8 ohm speakers and see what happens.

If the receiver still shuts down with two speakers, then you should get the unit serviced or replaced. Any number of things in the power supply could be at fault, and unless the problem can be replicated, it won't be easy to diagnose because the service tech won't use the same speakers that you use.

[This Guy]

And remember, not all 4 ohm speakers are created equal. You could take one 4 ohm nominal speaker, which stays a pretty easy load on most amps, because the impediance doesn't drop much lower than 4 ohms. Then you could take another speaker with a 4 ohm nominal impediance, but it would be much harder to drive because the impediance could go much lower than 4 at some frequencies. This isn't your fault because the manufacturers don't usually tell you the speakers lowest impediance. But this is why the Marantz is rated to handle no less than 6 ohm speakers, so it can allow those 6 ohm speakers to drop in impediance and still have them run fine. Just some general knowledge on speakers.

-Joey