Question about Denon AVR-3805 Receiver
If your amp looks like it's going to work as normal (ie the front display lights up as it should etc), but then the amp goes into protection mode when the anti-thud circuit times out, then I know what's likely to be wrong.
It's one of the power amplifier channels which has gone faulty.
I just found this out after having this problem with my AVR-1906.
I took the amp apart and de-soldered the suspected channel power transistors (centre channel in my case).....and hey-presto! it fired up as normal (obviously the centre channel would be out of service).
I have ordered the replacement transistors from Farnell (UK) at a miserly cost of around £2-£3 each.
Just waiting for them to arrive.
An alternative is, if you don't use all your channels, take the transistors from a known working but not needed channel and swap them over with the duff ones.
Hope thats of use!
Posted on Aug 16, 2008
It's likely that you have shorted some speaker outputs, I had that problem and sorted it. Unfortunately it does mean replacing some output transistors..the devices are dificult to get to just to add insult to injury. They are the devices that are mounted directly onto the large heatsink and solder connected to the bottom circuit board. You only have to change the matched pair that you have blown....tricky to identify which ones without some electronics knowledge. The power output section does have some fuses to protect it but sadly these do not appear to be fast enough to stop "one" from damaging the power output stage if you unfortunately short outputs. The transistors are available from Farnell, use pin compatible replacements SAP15N and SAP15P.....all the best. Doctor Bill
Posted on May 26, 2008
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