I very stupidly managed to short one of the output channels(surround back right, I think) on my reciever. I replaced the slow blow 3.15A internal fuse and it now tries to power up but goes into protect. Since I don't have ay circuit diagrams I took it to a local repair shop but they said it was rather a complex problem and they couldn't fix it without the service manuals/circuit diagrams. Surley this is likely to be an output transistor? The trouble is I don't know which one without the circuit diagram, and even then I'm not sure how to test it proprly to make sure. The other option is to buy a service manual from service manual.net but I don't want to do this if it's going top be no use, and I don't really want to take it to a denon dealer as the cost will probably be astronomical, and I was thinking of upgrading to a new onkyo soon anyway.
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Re: Blown output on Denon AVR3805
This unit does not use "output transistors". The driver section uses hybrid packs that are usually two to a set. Knowing which set to replace is only part of the problem when replaced as bias voltage Must be correct...accordianman
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I would also replace 2sa992 (2pcs) and 2sc1845 on preamp board- sometimes they look ok when you test them by regular meter. Check 1.2 kOm and 4.7ohm resistors at preamp pcb. Check diodes on output pcb (could be smd type, connected from base of output transistors to emitter i think)
Usually it is bad power supply problem or bad channel problem. Look for any burned parts, it helps you locate the problem. Burnt resistors in one channel- you need to replace output transistors (better to replace all transistors in that channel) and bunch other surrounding parts. If you do not see any burned parts, check all voltages coming from power supply +15 -15 +5 etc then check dc at every channel output (not at speaker terminals but at control pins on the amp/main pcb), should be +-10mV
Sure, if you want to hear Surround Back program material coming from the subs without midrange or tweeters. (Sarcastic) Of course, the LFE program material will still be going into a black hole somewhere.
Run the subs in series with each other -
Sub Amp negative to 1st speaker negative;
1st speaker positive to 2nd speaker negative;
2nd speaker positive to amp positive.
Run the speaker level adjustments routine and enjoy.
Just for giggles, try what you were thinking about. You won't hear much from the sub(s) unless you programmed the Surround Back channel as full-range and then have something like the Apollo 13 launch for program material. Normal audio won't send much low-frequency material to those channels. The optimal place for subs is on the LFE or sub channel.
I think your receiver has cracked main (amplifier) board close to surround back channel terminals. Need to take apart the receiver remove the board, inspect it and resolder cracked traces. Unfortunately it is not so easy to remove that board and probably you need to bring it to a repair shop.
Okay! all ceiling mounted speakers. I don't know about 4 pair of speakers.Here is the load down: First pair of ceiling speakers would be left and right front from speaker A or Main output behind your receiver. Second ONE,but a pair would be connect to the center channel output as your center speaker. Another pair would be connect to the surround sound left and right(NOT surround BACK left/right.) Now,you have 5 channel setup at this point,you still need to purchase a power subwoofer to the SUB PRE-OUTPUT behind your Denon receiver.
For Zone two,you would need to connect your other pair of speakers to surround BACK left and right output. Go to your Denon MENU button,depending on which model you have,some of them will have an on-screen display feature(you would need to have a composite video cable connect from the video output behind your receiver to the TV video input in order to use the on screen menu.)If not,you would have to it view on the front panel of the A/V receiver. You need to read the detail on how to setup the video and audio as well as distance and DB for the receiver through the menu button. I will be frank with you,if you are an amateur,Denon is NOT easy to be setup on the first time. solutiondoct
All of the Denon recievers I have repaired (over 100) that shut down after a very short time are going into protect mode. The display lights up and after about 10 seconds the display goes out and the standby led blinks red.
I have found that they have one of 3 possible problems and they all require that the reciever be taken apart and fixed at component level. No way to tell what your problem is until it gets put on a bench and troubleshot.
Problem 1. This is the most common problem. One of the front channels shorts out. On the big heat sink the front channels are at each end. It is the front left channel (close to the display) This requires that the output transistors be replaced as well as some driver transistors and some resistors and a capacitor. Lots of work for a blown channel. Denon has put out a bullitin to upgrade the bias transistor and change a couple of resistors to help compensate for this failure. That channel overheats more than any other channel.
Problem 2. There is a resistor that is right next to the preamp board that opens up. It is a 10 ohm 1 watt resistor and when it opens, it causes the unit to go into protect.
Problem 3. The +12 volt regulator fails. It is in the power supply area on a smal heat sink right next to the -12 volt regulator. Generic part number is KIA7812 It also causes the unit to go into protect.
Most decent repair shops can fix these from about $120 up to about $200. Depending on which problem it is and how fast they are at finding the problem. Most charge labor by the hour.