spirovious
Well-Known Member
Great to know that problem got solved finally.
My AVR Marantz 7012 randomly going in Protection
- Thread starter ankitbhargava
- Start date
ankitbhargava
Well-Known Member
Thanks to you and all FMs for all their helpful advise
Congratulations....glad it is finally resolved. Am sure the replacement module would have costed a bit.
amrutmhatre90
Well-Known Member
Akbar is a gem of a guy, MZ Audio deals with Marantz, QA, Taga and more. Very helpful and quick to reply even on mails!
sandeepmohan
Well-Known Member
Wow. Who would think that a network module can cause a circuit to trip! Goes to show how complex these things are built these days. I would have never thought of this.
I got to say that is good support from MZ Audio
I got to say that is good support from MZ Audio
ankitbhargava
Well-Known Member
Thank you
Yes very very helpful and always responsive
Since I ended up resetting AVR to original Firmware, I was trying to upgrade and I realised that Network wasn't working. I called up Akbar and he said the Module needs to be replaced and could be the possible reason of "protection mode".
I immediately decided to get replacement which was sent promptly by Akbar.
After replacement of the Network Module, the problem hasn't occurred.
happy me
superczar
Well-Known Member
- Joined
- Feb 5, 2008
- Messages
- 835
- Points
- 93
FWIW, this is not necessarily indicative of a bad ground.
Most AVRs use a non grounded chassis to avoid ground loop.
Easy to check as well, the mains inlet on the AVR will most likely be two pin.
(Ungrounded chassis combined with high-frequency hdmi connections will almost always result in a small floating induced ac on chassis)
Indeed. However these AVRs are two pin for a reason - To prevent the noise these units generate back into the mains. They have an internal SMPS to power the standby circuits. See a representative circuit below. Once you have an SMPS, there will be leakage from two or three places. One is the EMI filter. All SMPS require it to reduce the high frequency noise created by the switching mosfet or the PWM controller IC. The 240 mains voltage gets rectified and with the bulk capacitor C1 you now have a dangerous 339 volts DC (multiply RMS by 1.414). This voltage is then switched by Q1 to generate the desire voltage in T1. Here is where the second leakage happens. There always will be capacitance between the primary and secondary windings of the transformer T1, since they are wound on the same core. There is a third place where this leakage occurs. Since we have dangerous voltage coming inside, if any malfunction happens and the current from the live enters the circuit we can get electrocuted. So to prevent that we have two safety capacitors connected. One from the live to the ground and another from the neutral to the ground. The capacitors have to be of the same value. This capacitors will pass the live current in case of high leakage and they are designed to fail short. This will blow the fuse and hence electrocution will be prevented. But the side effect of having these two capacitors is again leakage when the capacitance value changes with age.
So, just because we have deployed a SMPS, we now have a situation where current from the mains has leaked to the 0 volts line in the below circuit. This 0v line will be the equipment chasis. Now If we connect the chasis to the earth ground, the current will find a way to flow back causing currents through unintended portions of the AVR circuit. This will cause noise. However most people (including me) will connect the AVR to a television set using a HDMI cable. The TV will have 3 wires and through the HDMI outer metal connector we have just provided the leakage current from the AVR to flow through the HDMI cable to the TV's earch connection. Similar thing will happen if we connect a pre-amp to the AVR and the pre-amp has a 3-pin plug. The moment you connect the RCA cable from the pre-amp to the AVR, you provide a path for the leakage current to flow through the RCA. These AVRs have a gimmick. My Yamaha has something called Pure Direct. It does improve the sound by switching off the power supply to the HDMi board, but the SMPS still remains on. So the 'Pure Direct' mode doesn't eliminate the entire noise.
Medical equipment have stringent controls and norms for this leakage current, but I have no idea how they are designed. Most of these AVRs have a good quality transformer inside and that too can by itself provide all the power needs. So why do they deploy a small SMPS for the standby circuit. This is to do with stringent Euro Norms which specify that equipment should have green power supplies which consume power in few miliwatts in standby mode. Transformer based power supplies are notoriously ineffecient. Even with no load, the large transformer of an AVR will draw power in watts. In contrast a SMPS is usually more than 90% efficient. With no-load, a SMPS hardly draws power.
I like it when you to divorce the equipment from the power supply (e.g. laptops). But for good sound, I avoid using AVR or any equipment that have these noisy SMPS for anything that values sound quality. Google, Amazon, even MI have done it right by having a separate 5v power supply that goes into their units (Chromecast Audio, firestick, mi box). But the purpose for good sound is defeated because they all use a 5v SMPS and SMPS will always leak some current. So ultimately they too are no better than units like apple tv which has 339 voltage right inside the unit.
image taken from
So what do you do when you want pristine sound.
0. Use an AMP with 3 pin plug
1. Turn off all your cell phone charges
2. Turn off the TV
3. Don't have your wi-fi router near your amp
4. Turn off your apple tv, chromecast, firestick mi box, etc (turn of the main power supply to them).
5. Since other in your household will be using laptop power supply, cell phone chargers, etc connected to mains, you will have EMI leaking into the mains. So use an EMI filter. Most old audio amplifiers, tube amplifiers, etc manufactured before the millenium did not have any SMPS inside. So they will not have any EMI filter for the mains. So this is what I do. These EMI filters cost around 300 bucks. I use this with my stereo amp. This is exactly what so many (fake) power conditioners do. I know one which costs more than a decent amp but actually has passive LCR component inside..
6. Use an isolation transfer (maybe this should be the first thing).
Last edited:
spirovious
Well-Known Member
Was it easy to replace? Any soldering done?
spirovious
Well-Known Member
Most of TVs have only 2 pin at other end(TV panel in) even if 3 pin @ AC socket(plug).
If it is two pin, it is ok and the avr is connected to sources, none of which have 3 pins, then fine. But both my TV (one LG lcd and one Panasonic plasma) have 3 pin plugs.
spirovious
Well-Known Member
My TV has 3 pin near ac socket and actual input in TV is 2 pin Same like Pioneer BDp ,one side 3 pin and other side 2 pin
Don't know actual advantage as ultimately TV/BDP running on 2 pin only.
No soldering. This was a simple crimping job. I just cut a cord with plug and IEC socket and have plenty of these connectors
My TV actually has earth connected. Multimeter shows connections between RCA ground, HDMI ground to the socket earth connection. My Polk subwoofer has three connections but only two are connected.
ankitbhargava
Well-Known Member
was straight connector to the Pin, very easy
spirovious
Well-Known Member
Thanks for update. When I opened 6011 for cleaning, I found wifi antenna cable soldered on PCB. So asked.
Just a quick note - I just had this similar scenario on a sr7015. Checked all the cabling - finally narrowed it down to a faulty hdmi input which was giving an electrical shock. So make sure you check your HDMI as well !
What if marantz in not a warranty. Though this gem will replace this?
amrutmhatre90
Well-Known Member
No, but can repair it or help in repairing but will charge.
I have an SR7012 and facing sporadic DC protection issues for almost two years now. I ended up buying another AVR and now, one week later, my Blu-Ray player died having a faulty flyback diode in the power supply. Now I am thinking about whether this could have caused my DC protect issues all the time.
As this seems to be a common fault in Sony UBP-X800 players: Other people here don‘t happen to habe this particular player attached via HDMI as well?
As this seems to be a common fault in Sony UBP-X800 players: Other people here don‘t happen to habe this particular player attached via HDMI as well?
Anyone who has DC protect issues is using a Sony UBP-X800 Blu-ray disc player?
I have been experiencing sporadic DC protect issues for almost two years now. Recently my BD Player failed on a broken power supply (shorted flyback diode on secondary side of SMPS). I guess this power supply board could have been generating voltage spikes over mains or HDMI for a long time before failing completely.
I have been experiencing sporadic DC protect issues for almost two years now. Recently my BD Player failed on a broken power supply (shorted flyback diode on secondary side of SMPS). I guess this power supply board could have been generating voltage spikes over mains or HDMI for a long time before failing completely.
Check out our special offers on Stereo Package & Bundles for all budget types.
Similar threads
