Originally Posted by strtgng
Hi all. I’m looking for advice on what is turning into a very frustrating experience with my Denon 1910. I bought it new from Crutchfield in June 2010 and it worked perfectly for the first 2 years. I have an ATT Uverse cable box, PS3, and Xbox360 hooked up to it all via HDMI, plus a Wii with component cables. It outputs to a Samsung 50” plasma via HDMI. Speakers are some ancient Bose Acoustimass 7 front and center channels and JBL bookshelfs in the rear. There have been no changes to speakers or inputs other than a switch from DirecTV to ATT Uverse about a year into ownership of the Denon. Everything worked great for the first two years.
Last summer (right after the end of the two year warranty, naturally) the unit started to occasionally go into protection mode with the rapidly blinking red light. This was the every .5 second blinking light for a speaker short – not the overheating light sequence of 2 seconds. It started happening more often, to the point that it would go to protection mode in under a minute even if it had been off for days no matter what the source was. Heat isn’t the issue. It rarely gets played at anything above moderate volume as I have a small house and two young kids.
I have tried:
Swapping speakers as the Bose are very old and may or may not be 8 ohm depending on who you believe (but they are fully functional with two other older receivers I own)
New banana plug connectors
New speaker wire everywhere
Disconnecting all inputs/outputs other than 2 channel speakers and just playing the radio
Removing the unit from its normal location (where it has had 6-7 inches of ventilation on top and has worked fine since 2010)
Reseting the microprocessor per instructions on page 64 of manual and again on 12/14 per instructions over the phone.
Blowing compressed air in the headphone jack
All result in the same thing - the unit makes some very load "thumping" noises then trips the protection circuit. Typically within a few minutes, but when the issue first started occurring over the summer it would sometimes take longer. After some back and forth with Denon, they agreed to a onetime warranty exception and I shipped the unit to a Denon authorized repair center. A month later it comes back, and in speaking with the repair guy on the phone he claims they had it hooked up playing music for 5 days straight without any issues and it tested fine. I get it back and hook it up in my garage with no inputs other than radio and some 25 year old JVC tower speakers – it plays fine for 5-7 hours.
A few weeks later I finally have time to put it back in my main system, thinking it must be an issue with my Bose and JBL speakers based on the repair shops findings and it working with the JVCs – and I have wanted to upgrade to some Take 5 Energys, so I’m okay with dumping the old speakers. But until I can buy those new speakers, I connect the Denon to all the same components but switch the sound to just pass the signal to the TV to output sound. Basically the Denon is just being used as a very expensive HDMI switch as no speakers are connected and the TV is doing the sound amplification.
An hour into watching TV, the Denon protection kicks in. THERE ARE NO SPEAKERS CONNECTED! The unit was cool to the touch. The only thing I can think of now is that I have all the entertainment system components plugged in through a very large APC battery back up unit (as they have been since 2010) I suspect that APC battery back up is starting to lose the ability to hold a charge. My brain tells me this shouldn’t matter while the APC is plugged into the AC and back in the summer I had tried swapping outlets when I originally was troubleshooting, but I plug the Denon directly into the wall – and it ran fine for a few hours last night - but I have no trust in it not kicking off again. We shall see.
Keep in mind my 10 year old Kenwood 1080vr was swapped into the place of the Denon and has been driving the same speakers, plugged into the same APC unit, etc with only the inputs changed since it is too old to have HDMI. It has been playing fine for at least a month like this.
I am at a loss – I paid $400 for this in 2010. I expected more longevity than 2-3 years! Every other receiver I have ever owned still works 10-20 years later! I really am out of ideas of how to fix this. I don’t think Denon is going to offer anything now that their repair shop has said the unit works fine.
Any ideas? Am I missing something that I should test?
So I give up...
To continue the above saga, I pulled the UPS battery back-up totally out of the system. There is only a monster cable brand surge protector being used now. I plugged the 1910 in and have been using it since I made the above post on 2/26 without speakers hooked up - basically just using it as a HDMI switch. It worked flawless for 3 weeks, so I then plugged the speakers back in and they successfully played via all inputs without issues for over a week with considerable use each day (probably 8-12 hours constant use per day of either TV, PS3, or radio).
Trouble began this past weekend when I head a thump from the rear speakers and then no sound from the 1910. It hadn't kicked on the protection circuit - but no longer had sound. Using the volume button on the remote to turn it up one increment immediately restored the sound. A few minutes later there was another thunk from the rear speakers and the protection circuit kicked on. I turned the unit back on and went to look at the connection on the rear speakers and the plugs into the wall (which connect to wiring in the basement which then comes up on the other side of the room where the 1910 is located). As I leaned over to look, the couch moved under my hand and the protection circuit kicked on again. It hit me that the banana plugs behind the couch stick out enough that they rub ob the rear of the couch and most likely as people shifted weight on the couch the plugs shorted against metal bracing through the thin rear upholstery. Fine - easy fix by either getting lower profile plugs or making some sort of shield to go on the back of the couch. But until then, I disconnected the rear surrounds from the back of the 1910. Problem solved, I thought, and I fired up the receiver again with just the front 3 speakers.
Everything worked fine for about 2 hours, then there was several very loud thumps in the front speakers followed by the protection circuit kicking off again, The unit was barely warm to the touch, playing low volume, and nobody even in the same room at the time. I've yanked the speakers back off and routed the audio to the TV speakers and again am using the 1910 as a $400 HDMI switch...it has worked fine like this for 3 days now.
I am at a total loss now. I understand the rear speakers shorting... but what in the world is going on after they were totally removed from the mix? The battery back-up that was going dead is also out of the loop. This receiver and speaker combo worked without issues for the first two years, in the same location. The same speakers work fine with a older Kenwood receiver hooked up on the same place as the 1910, plugged into the same outlet, using the same wires, etc.
I'm running out of rational sounding theories and I'm down to these somewhat far fetched ideas:
- The Bose speakers are slowly killing the 1910 - maybe the 1910 can't drive them as well as the older Kenwood, or is more sensitive. Bose doesn't give too many specs and simply say the work with 4-8 ohm systems...but if the 1910 needs 8 ohm speakers and the Bose are more like 6 ohm, then do they just put a strain on the system? Of course this theory doesn't explain why they worked just fine for two years...
- There is some sort of intermittent flaw in the circuitry of the 1910 that causes this issue - it would have to be amp related which would explain why the 1910 works fine when the amp is basically off because no speakers are connected and the sound is routed to the TV. But what causes it to start? The unit isn't being moved or jarred by anything.
- There is some sort of power issue in the house. Now I have lived in this house for 12 years and never had any other issues - the house was built in 1996 so it isn't ancient wiring. The 1910 has lived in the same spot the entire time, plugged into the same outlet through the same APC UPS. BUT, did the UPS supply it a "clean" power supply which masked the problem for the first two years and only when the UPS battery started failing did the issue start getting passed through the UPS to the 1910? Not sure about this, as even if the battery in the UPS is dead, it still is plugged in and passes power as an expensive power strip...but maybe it can't regulate voltage as well. Why wouldn't this impact the TV, Xbox, PS, or cable box also hooked up to the same power...or the older Kenwood receiver when I used it?
So I'm frustrated and tired of trying to track this down. Anyone have any more ideas?