Marantz SR7010 - Protection mode , blew transistors twice!

[PENG]

Just took the bad boy out.., dont see any burnt marks anywhere
View attachment 32995
View attachment 32996
View attachment 32997

Looks good! Seems that it is now down to two things: a) the speaker feed wires have a fault that is somehow intermittent, or b) the receiver has an intermittent internal fault that the service tech missed, it is easy to miss if the fault did not reveal itself at the time.

What kind of speaker wires did you use? Is it the regular type that if pinched the right way, a short could be created?

 

[AVUser001]

What kind of speaker wires did you use? Is it the regular type that if pinched the right way, a short could be created?

This one Mediabridge 12AWG 2 conductor CL2 rated. Sturdy and flexible..

 

[lovinthehd]

How about checking inside the speakers?

 

[AVUser001]

How about checking inside the speakers?

I dont want to void the warranty..and its working fine.. you could see most of it anyways, no signs of damage.

 

[lovinthehd]

I dont want to void the warranty..and its working fine.. you could see most of it anyways, no signs of damage.

You can see most of the innards of the speakers from the outside? I can look inside a speaker without anyone knowing but me in any case....and have done so as warranty claim is something I've never had to use on a speaker....

 

[AVUser001]

You can see most of the innards of the speakers from the outside? I can look inside a speaker without anyone knowing but me in any case....and have done so as warranty claim is something I've never had to use on a speaker....

Yes, I have special glasses ;-) , Seriously, dont want to, to go along this line of diagnostics. Appreciate your suggestion, anyways.

 

[lovinthehd]

Yes, I have special glasses ;-) , Seriously, dont want to, to go along this line of diagnostics. Appreciate your suggestion, anyways.

Since they're working fine with the Denon I think it's probably not likely to yield fruit....I'm still leaning towards the Marantz for that reason.

 

[mtrycrafts]

Those are two different tests, I did.
1) Passed a short 9v DC ( ~1-2 seconds) to each of the speakers using a 9v battery and observed audio.
...

Late to the party but that 9V dc may not be a good idea even for a second or two. I'd use 1.5V batteries for a quick check

 

[M Code]

I would surmise U have an internal problem within the Marantz....
When U took it to the service center, the tech found the (2) blown output devices... Replaced them, played the unit for a short time and assumed all is OK... If U had a short in 1 of your loudspeakers and/or respective cable the receiver would have shut down and triggered its internal protection scheme....
Assuming the receiver has adequate free-air clearance, today the majority AVRs are well built, and most technical issues are software related rather than hardware.. If possible, I would suggest U push the dealer or Marantz and get the unit exchanged.....

Just my $0.02...

 

[AVUser001]

If possible, I would suggest U push the dealer or Marantz and get the unit exchanged.....

thanks..but this is a 4yr old unit, out of warranty. Its still under repair warranty of Panurgy though ..,but havent hooked up yet, after it came back from the 2nd round of transistor replacement.

 

[TLS Guy]

thanks..but this is a 4yr old unit, out of warranty. Its still under repair warranty of Panurgy though ..,but havent hooked up yet, after it came back from the 2nd round of transistor replacement.

I did not realize that unit was that old. After researching it, I see that unit is not well thought of. There are now a lot of consumer reviews. It seems 40% of customers reporting have had serious issues. Your issue among them, of protection and blown transistors..

I now suspect you have to cut your losses. From what I now know, I would either ditch the unit or remove all the amp boards and just use it as a pre/pro.

I honestly will be surprised if these sort of reports do not become common place as we get more of these 9.2 and 11.2 receiver out there. I really think this whole concept is going to produce a lot of misery to give you company.

No one is going to convince me that going down this route is anything but absurd. If any of these type of units prove to have longevity I will be really surprised. I would never think of owning one, let alone recommend it to anyone.

 

[AcuDefTechGuy]

Since they're working fine with the Denon I think it's probably not likely to yield fruit....I'm still leaning towards the Marantz for that reason.

Yeah. I agree. If the same speakers work perfectly fine with the Denon, then the speakers are probably fine.

 

[PENG]

I did a text search on avsforum and avforum. It did not find any reports of protection mode/transistor blown related issues. Then search Amazon 1/2 star rated reviews and found quite a few reports of having to send back for shutting down but no report of blown transistors (doesn't mean it didn't happen).

If you do a detailed text search you will find reports of the AV7702 (the AV7702 MkII was the equivalent AV to the SR7010) shutting down and other issues too though there were fewer (about half) 1-star ratings on Amazon than the SR version.

Don't forget the AV version of the SR differences are only/mainly in the following.

On the plus side:

The AV version does not need to deal with the heat from the power amp section, and it has more space to breathe too.

On the minus side:
- It has the unbalanced circuitry/components, and the associated additional heat from the additional HDAMs (though minor).

Overall, I highly doubt theoretically speaking the AV version would be that much more reliable than the SR version especially if external fan(s) is/are used.

TLSGuy: I strongly suggest you use an external fan if you want to external the life of your AV7705 unless it is very well ventilated. It may have a fan that is hidden from plain view but the schematics of the 7704 and even the 8805's schematics show there is "fan control". They do that for a reason, trouble is, they don't typically had the set point too high for my liking, obviously ymmv..

For most users in small to medium size room driving 8 ohm nominal speakers, an AVC such as the 7705 would run almost as warm as the SR7013. When I had the AV8801 for the HT I had to use two fans to make me feel like it would last forever, otherwise it just felt too warm to the touch but that's just me.

 

[PENG]

Yeah. I agree. If the same speakers work perfectly fine with the Denon, then the speakers are probably fine.

As I said earlier I am now leaning towards the Marantz itself too, that Panurgy missed an intermittent fault/short somewhere in the output stage. It won't be software related as that would cause nuisance shutdowns that some users experienced but wouldn't have caused output transistors to blow.

 

[AcuDefTechGuy]

As I said earlier I am now leaning towards the Marantz itself too, that Panurgy missed an intermittent fault/short somewhere in the output stage. It won't be software related as that would cause nuisance shutdowns that some users experienced but wouldn't have caused output transistors to blow.

What? Panurgy missed something? No! Can't be!

You know how much I HATE Panurgy.

 

[TLS Guy]

I did a text search on avsforum and avforum. It did not find any reports of protection mode/transistor blown related issues. Then search Amazon 1/2 star rated reviews and found quite a few reports of having to send back for shutting down but no report of blown transistors (doesn't mean it didn't happen).

If you do a detailed text search you will find reports of the AV7702 (the AV7702 MkII was the equivalent AV to the SR7010) shutting down and other issues too though there were fewer (about half) 1-star ratings on Amazon than the SR version.

Don't forget the AV version of the SR differences are only/mainly in the following.

On the plus side:

The AV version does not need to deal with the heat from the power amp section, and it has more space to breathe too.

On the minus side:
- It has the unbalanced circuitry/components, and the associated additional heat from the additional HDAMs (though minor).

Overall, I highly doubt theoretically speaking the AV version would be that much more reliable than the SR version especially if external fan(s) is/are used.

TLSGuy: I strongly suggest you use an external fan if you want to external the life of your AV7705 unless it is very well ventilated. It may have a fan that is hidden from plain view but the schematics of the 7704 and even the 8805's schematics show there is "fan control". They do that for a reason, trouble is, they don't typically had the set point too high for my liking, obviously ymmv..

For most users in small to medium size room driving 8 ohm nominal speakers, an AVC such as the 7705 would run almost as warm as the SR7013. When I had the AV8801 for the HT I had to use two fans to make me feel like it would last forever, otherwise it just felt too warm to the touch but that's just me.

The 7705 does only gets very slightly warmer than the surroundings. It is in a professional 19" rack and has clearance all the way round and below. I'm using the Marantz rack mounting brackets that I always have. The two older 7701 pre/pros are now mounted in cases but with good clearance. Both have temperature probes and fans that come on in response to rise in temperature. The temperature is continuously displayed. The head units with the display have never registered more than 3 degrees C above ambient temperature. Interestingly the power consumption of all of them is the same which is 60 watts. In addition with no power amps, the units are very open inside, with lots of empty space.

The power amp case in the studio does generate significant heat. There is a variable speed Fantech unit in rafters that pulls air continuously from above the amps. This fan tuns on from the relay that starts the three Quad 909s that power the front left and right speakers.

This really is the same design as before, except for the use of professional racks rather then my racks. The new racks are even more open. Interestingly my first Marantz pre/pro the 8003 made significantly more heat than the others, and had a higher power consumption as well. This is of course true for computers as well. My original DAW generated substantial heat, but the 4K HTPC and the new DAW make practically no heat at all. So new processing technology is much more energy efficient. However I understand it is less tolerant of running hot. This is another very good reason for not crowding processing circuits with power amp circuits.
So I do think I'm on firm ground considering 9 and 11 amp channel receivers as highly likely to be trouble prone, fans or not, and best avoided.

 

[AVUser001]

Wanted to update on some quick testing , I've been doing with the Marantz, now hooked up to a new Dayton audio cheapish speaker(rated 6 Ohms, 87 dB, 40W RMS/75W Max), based on PENG's suggestion.

Just used one speaker, to test the channel in question(FRONT LEFT)

Test 1:
Speaker connected to AVR's FRONT LEFT direct.
This was the amp channel, where repair guy replaced transistor.
Audyssey test tone sounds OK. Test track , pushed all the way (gradually) to -10dB sounds OK.

Test 2:
Speaker connected to AVR's HEIGHT2 LEFT/FRONT WIDE .
This was the same terminal the B&W TOP REAR LEFT speaker was connected to, when the transistor blew. I had to set the Amp Assign to FRONT WIDE, to push audio into this channel. Otherwise, all other combinations route audio only to HEIGHT 1 channel.

Audyssey test tone sounds OK. Test track , pushed all the way (gradually) to -10dB sounds OK.

Test 3:
Speaker connected to Emotiva PowerAmp's CH1 , fed from AVR's FRONT LEFT Pre-Out.
Just wanted to make sure there is no issue with FRONT LEFT Pre-Out and Emotiva's CH1 load. On Incident 2, I felt, the AVR went to protection mode, when the 12v DC trigger kicked-in & PowerAmp came alive.

Audyssey test tone sounds OK. Test track , pushed all the way (gradually) to -10dB sounds OK.
Emotiva pushed the speaker even further....didnt want to blew up this 75W max speaker!

@PENG , any other tests with this test speaker, do you suggest ?
I can (& probably should) connect both the test speakers , to test all the channels , one by one..but wanted to get the FRONT LEFT out of the way , first.

 

[PENG]

Wanted to update on some quick testing , I've been doing with the Marantz, now hooked up to a new Dayton audio cheapish speaker(rated 6 Ohms, 87 dB, 40W RMS/75W Max), based on PENG's suggestion.

Just used one speaker, to test the channel in question(FRONT LEFT)

Test 1:
Speaker connected to AVR's FRONT LEFT direct.
This was the amp channel, where repair guy replaced transistor.
Audyssey test tone sounds OK. Test track , pushed all the way (gradually) to -10dB sounds OK.

If you left the setting as shown in the screenshot, that is the same as mine, you shouldn't get any sound connecting to the front left because it would have been assigned to "front wide/height2 according to the manual?

 

[PENG]

Until I can get a clear definitive answer to my question I don't feel comfortable suggesting the next test.

 

[AVUser001]

If you left the setting as shown in the screenshot, that is the same as mine, you shouldn't get any sound connecting to the front left because it would have been assigned to "front wide/height2 according to the manual?

Correct, call that as the baseline Test 0 .., with my previous config posted earlier ( ie Front Left Pre-Outted), No sound from FRONT LEFT , as expected, becos its Pre-Outted.

I wanted to test the different scenarios , with actual speaker load , exercising the Front LEFT Channel Direct, Height 2 Left Direct , as well Front Left via Pre-Out. Those are the 3 scenarios I posted above.

But yes , the original config produces no sound on FRONT LEFT as expected. Also, when speaker connected to HEIGHT 2 in the original config, Test Tone was OK on Top Rear Left.