Need Help Troubleshooting Denon AVR-2805

glemay

Hey,

I've been having some trouble with my Denon AVR-2805 for the past week. Hopefully someone can help me troubleshoot it and maybe I just did something wrong.

Anyway, the receiver is not outputting any sound from any source in any mode except "Pure Direct" which if I understand correctly bypasses much of the electronic circuitry. This worries me because it leads me to believe there may be something wrong with an electronic board in the receiver.

Anybody have any ideas I can try?

Thanks,

Jerry

glemay

Anybody have any suggestions? I spoke with Denon Tech Support but they could not provide me with much help. Suggested I bring the unit into a repair shop... I wonder what it might cost to fix and if it's worth fixing? Thoughts?

DON73

glemay wrote: »

Anybody have any suggestions? I spoke with Denon Tech Support but they could not provide me with much help. Suggested I bring the unit into a repair shop... I wonder what it might cost to fix and if it's worth fixing? Thoughts?

I had the same Receiver and had a problem with the digital circuit and ended up giving it away because the cost of repairs would be over 60% of a new receiver. Very nice sounding receiver while it was working properly.

glemay

Well that's unfortunate to hear. Looks like I may be on the sidelines for awhile...

TECHNOKID

glemay wrote: »

Well that's unfortunate to hear. Looks like I may be on the sidelines for awhile...

glemay, don't go too fast with conclusions. Have you done anything out of the ordinary lately to/with your set-up? Did you have to fidle with any connections (some as simple as wrong or loose connections... some you may not think of)?

Personally, I would start fresh and new. Power down everything, physically remove all connections, check them out carefully. Redo your mic calibration and whatever programmable set-up you may have done manually. Maybe the board is just hung up (hopefully). Oh, don't forget to take notes of your settings before going too far with the above.

Now, you know you are bypassing some of the electronics but you also know the amplification stage are working since you get sound out of your speakers when in pure direct.

How old is your unit? Do you feel at all comfortable removing the cover (of course only after unsuccessfully trying the above connections and calibration refresh and obviously making sure the unit is unplugged)? Any knowledge of electronic components?

If this at all in your ability, your first step would be to physically check if any board have lifted pins (not fully knowledgeable of your specific receiver but nowadays, many smaller boards are "pinned stacked" over the main board and may come loose over time). Make sure you do not touch ICs and/or OP amps with bare fingers as those small components are alergic to body static and you may cause worse problem. Do you own a static strap? I hope I am not going too deep here?

Now, if you do see some like that that is obvious enough that you can set back in place then we go into deeper into the small electronics and if you have good eyes and a strong magnifier, you could look for physical cold joints in the solder of the surface mount components. Don't forget to look for physical burns on the boards, burned components etc...

I may be going over your head here but not knowing you and your abilities, I am just pounding the keyboard as the toughts are coming of my tiny brain. I have to go soon (1 hour drive back home) but I will try to see if your posted any thoughts or concerns before I hit the sac for the night. In the mean time, maybr someone that knows better will hopefully chime in.

Good luck for now and hopefully talk to you a little in maybe an hour an a half...

Now, if you look at the last post of the below AVS discussion, the guy had his fixed and the problem was actually cold soldering (which does not surprised me a single bit, darn Chinese manufacturing! ).

http://www.avsforum.com/avs-vb/archive/index.php/t-901768.html (remember, last post) Do you have dexterity, soldering skills and good vision? Otherwise, get an estimate before your local tech fidles with it. You might be lucky and get it fixed at decent pricing. IAW, talk to you later maybe (I think you are no longer on line at the present time)...

TECHNOKID

BTW, have you done a reset of your unit? Check your manual, there is apparently details of how to do a hard reset of your Denon at the end of your manual in the troubleshooting section.

Good luck!
TK

glemay

Haven't had much time lately to check out my receiver, so busy with work. But I will post back later this evening. Thanks TECHNOKID.

glemay

Looks like I have a little bit of time.

Anyway,I have already done a hard reset. I've also disconnected everything from the receiver, including all electronics and speakers. I then started hooking up just two speakers and was going to simply try the receiver that way but had no luck. Even Pure Direct now seems to be hit or miss. The receiver will sometimes work and sometimes it won't.

I'm having a hard time figuring out the pattern, but it almost seems as if it will work on whatever settings it was turned off with. So if I power it down in 5CH stereo with Turner as the source, and I previously had no sound, it will work with those settings the next time I power it up. However, as soon as I make a change to any of the settings, source, surround mode, etc. it will stop working until I turn it on the next time. The weird part is, sometimes it will work the next time I turn it on, and sometimes it won't. Hence the difficulty in determining the pattern.

The unit is about 6 years old. I have had the top cover off and was looking at everything visually. I'm no expert with electronics, but I've learned what to look for somewhat. All the boards looked to be seated correctly. I did not see any burn spots on any of the boards. I did not touch any of the ICs or OP amps.

That's all I can say for now. I'm going see if I can get a family friend to look at it. Apparently he has quite a bit of experience with electronics and the like...

Thanks again TECHNOKID

cnh

Don't have anything to add to what TK has already said, but I am surprised that that unit is acting up? Those earlier Denons were better built than the more recent stuff. I have an AVR-2807, two years younger than yours--never had a problem with it (knock on wood). Those units from the 2807 and under were Japanese manufacture and generally pretty well put together.

Hopefully your friend can turn up something. Was the unit well ventilated throughout your ownership?

Good Luck!

cnh

TECHNOKID

What you describe leads me to beleive it might be the processor and since it is intermittent, it might some as simple as cold joints around the processor circuit. By any chance, have you noticed any changes as the receiver warms up? IE: does it work for a bit and then craps out on you, this would also lead to cold joints... If the family friend is somewhat qualified, with the detailed info you are providing he should be able to nail the problem for you.

Good luck anyway (and keep us posted )!
TK

TECHNOKID

cnh wrote: »

Don't have anything to add to what TK has already said, but I am surprised that that unit is acting up? Those earlier Denons were better built than the more recent stuff. I have an AVR-2807, two years younger than yours--never had a problem with it (knock on wood). Those units from the 2807 and under were Japanese manufacture and generally pretty well put together.

Hopefully your friend can turn up something. Was the unit well ventilated throughout your ownership?

Good Luck!

cnh

Cnh, I agree with your about the better manufacturing comment however, as early as the mid 80s (http://en.wikipedia.org/wiki/Surface-mount_technology)many of the Japanese manufacturing was subed to Mexico and the coming of surface mount components is also a real pain. Light suface soldering and the flimsyness of such circuit just make it easier to fail due to poor solder. When I was in the manufacturing sector, I was troubleshooting brand new boards fresh out of the subcontractor and you would not believe how many problems were cured by simply re-touching surface mount solder. The runs are also small and flimsy and we had a team of Asians workers on each shift to redo busted runs for us with tiny short strap wires.

The reliability of solder joints become more of a concern as less and less solder material is allowed for each joint. Voiding is the phenomenon that is commonly associated with solder joints especially when reflowing a solder paste in the SMT application. The presence of these voids can deteriorate the joint strength and eventually lead to joint failure.[

Your point about heat is also bang on/quite relevant as cold solder joints will promptly react to heat built up and definitely appear way quicker than a well ventilated unit. Power surge and spikes are also an issue with such miniaturized circuit such as surface mount. I can recall during the 1998 Canadian ice storm (http://canadaonline.about.com/cs/weather/p/icestorm.htm), when the electricty companies started the power restoring process, I had installed bunk beds in my shop, up early mornings, going to bed late at night working on power supplies and processors damages due to spikes caused by the power restoration.

Any type of equipment (TVs, VCRs, receivers etc.) using the smallish surface mount technolgies is prone to fail prematurely under conditions such as heat built up, power surge/spikes. This was not as common in the older days of through hole components. Was power surge protection that popular then? NOT so much but for today's technologies it nearly is a must.

Power was restored in most urban areas in a matter of days, but many rural communities suffered for much longer. Three weeks after the beginning of the storm, there were still 700,000 people without power.