Receiver issue..protect mode & such

[cobbpa]

I own a Marantz SR5600 and have built the front 3 speakers. The impedances dip low in some spots for these speakers, but I've not had any issues until today. I typically listen with the volume at -29, but for movies or music when I want them loud I go as high as -13, but -19 or -17 usually does the trick. I've had them that loud for over an hour before. The receiver gets pretty warm on top, but it never slows down or turns off.

Until today. I watched MI:3 at normal (-29) volume, then went back to watch the bridge scene. I set the volume at -17. About 30 seconds in, my receiver screen shows PROTECT and the sound turns off. Freaked me out, honestly. I started the scene over at a lower volume, then once past that point turned it up again. This time the Marantz turned completely off, no TV display even, and the red 'standby' light started blinking. I thought it must be the audio on the DVD, so I put in a music CD. Same thing..once I get any louder than -19, it stops. It isn't even really warm, no where close to as heated as I've felt it before. All I find in the manual is, "After “PROTECT” appears on the unit’s display, the standby indicator may start flashing. If it does, there is a problem in the unit or the connection. If this problem reoccurs even when power is activated from the remote control unit, call for servicing." That's the only time it mentions PROTECT being on the display. Turning it on now, the light does not come on, but after less than 10 seconds of music at volume -23, it starts switching in & out of protect, but not blinking the standby light. I'm trying it right now at -29 and it's gone several minutes with no problems.

Any advice? I don't want to be limited from volumes previously ok, but I don't want to damage the receiver either. Music still sounds fine, there's no problem there, just the protect mode that has never happened until about 30 minutes ago! :M

[Arneson]

Here is a simple test and easy to do.
Assuming there are two channels, take two spare speakers and temperarily wire them up in series with the speakers you suspect may have an impeadence issue.
This will lighten the load on the system and see what the results are.
Personally I would also do a visual and a smell test inside the unit, you may not be overheated now but may have previously.

[cobbpa]

I'll do that, but I should clarify..I know that these speakers dip to low impedances. Across one frequency they touch 3 ohms, their lowest point, but besides that they're all pretty reasonable..up above 5 ohms for the most part.

I don't think I understand how I may have previously overheated it even though it's been working well. Could you maybe explain that a little, please?

Edit: Interestingly, I unplugged it to check and be sure no wires were touching in the back. I examined the speaker terminals, too..they seemed fine except that it looked like my ipod's 3.5mm to RCA end was touching one speaker terminal. Could this have caused problems? I turned on some music fairly loud for about 10 minutes, no problem. Now I have Sin City playing in DTS at -29, but have made a point to turn it up during a couple of fight scenes. No problems thus far. Hmmm..

[Arneson]

As an example, someone brings me a set that has for absolutely no reason malfunctioned.
Come to find out, someone had put a magazine, LP cover, etc, on top of the unit.
It would not take long for things to heat up. Just a hypothetical of course, but these kind of things we tend to forget with time.
Now that you've mentioned something that sounds like a short of some kind on the output, I would for sure open the lid for that visual. You're looking for a discolored resistor or a burn smell near the large heat sink.

[whoaru99]

I own a Marantz SR5600 and have built the front 3 speakers. The impedances dip low in some spots for these speakers, but I've not had any issues until today. I typically listen with the volume at -29, but for movies or music when I want them loud I go as high as -13, but -19 or -17 usually does the trick. I've had them that loud for over an hour before. The receiver gets pretty warm on top, but it never slows down or turns off.

Until today. I watched MI:3 at normal (-29) volume, then went back to watch the bridge scene. I set the volume at -17. About 30 seconds in, my receiver screen shows PROTECT and the sound turns off. Freaked me out, honestly. I started the scene over at a lower volume, then once past that point turned it up again. This time the Marantz turned completely off, no TV display even, and the red 'standby' light started blinking. I thought it must be the audio on the DVD, so I put in a music CD. Same thing..once I get any louder than -19, it stops. It isn't even really warm, no where close to as heated as I've felt it before. All I find in the manual is, "After “PROTECT” appears on the unit’s display, the standby indicator may start flashing. If it does, there is a problem in the unit or the connection. If this problem reoccurs even when power is activated from the remote control unit, call for servicing." That's the only time it mentions PROTECT being on the display. Turning it on now, the light does not come on, but after less than 10 seconds of music at volume -23, it starts switching in & out of protect, but not blinking the standby light. I'm trying it right now at -29 and it's gone several minutes with no problems.

Any advice? I don't want to be limited from volumes previously ok, but I don't want to damage the receiver either. Music still sounds fine, there's no problem there, just the protect mode that has never happened until about 30 minutes ago! :M

You've probably already done this, but the first step is to check very carefully/thoroughly for any fine strands of loose speaker wire shorting to another terminal or to the chassis. It's often dark behind the rack or entertainment center and hard to see those fine strands. Check at the receiver terminals and also at the speaker terminals themselves. Also check the speaker wire for damage over it's whole length. This I would do before opening the unit.

Maybe something came loose inside one of the speakers (crossover parts) and is causing a short.