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  • Anonymous Nov 17, 2008

    Denon 2105 amp.

    symptoms, switch on green led flashes 4 secs then red flashing "Protection Mode".

    Tried the following:-

    reset using a+b buttons.

    replaced ic101 ic102 1c104. (+15/-15/+5 volt regulators).

    Checked r184 10ohm resistor OK.

    Unsoldered and measured all 21 output transistors. All seem ok.

    Checked for dry joints, any suspects esoldered.

    All tests carried out with no inputs or outputs connected.

    Found 10mfd 50volt and 100mfd 10volt electrolytics in one of the preamp channels very low capacitance, replaced.

    checked all capacitors in power supply and all on pre-amp board for capacitance value and ESR, all ok.

    checked +/- 53 volts at collectors of o/p stages before protection operates, all ok.

    all buttons and knobs operate at switch on before protection.

    What can I try next. have all necessary test equipment but no circuit diagram. Can you help please. Regards Alan.

  • alang4vou Nov 17, 2008

    Model avr-2105
    Symptoms:- switch on, 4 seconds later red led lashing "Protection mode".Display ok and all

    buttons/knobs work ok for 4 seconds.

    Tried Reset a/b plus switch on.
    replaced ic1-ic2-1c4.+15/-15/+5 volt regulators.
    Checked r184 10ohm ok
    found 10mfd 50volt and 100mfd 10volt capacitors in one of the preamp channels low capacitance,

    Unsoldered and checked all 21 output transistors (2sd2390/2sd947f/2sb1560) all appear ok
    checked capacitance value and esr of all capacitors on preamp board and power supplys, all ok.
    Checked for dry joints and resoldered anything suspicious.
    no inputs or outputs connected during testing.
    Do not have service manual or circuit diagram so not sure what to try next, can tou help please.

    Originally went off due to playing too loudly for 1 hour.

    Regards Alan.

  • imoda4 Mar 09, 2009

    I get the red flashing light as well. I recently moved my amp and speakers. When i powered it up again i was running it fairly loud for about 5 mins then a series of blue flashes came out of the amp and a puff of smoke. I checked all my connections and found one wire on the right front speaker had come out at the speaker.

    I have taken the cover off the amp and removed the preamp board. Ii can see the fried components. They are on the bottom mother board located between the preamp and amplifier heatsink. R115C is half missing and the surrounding components R 117C, Q104C, C105C and D143 are a bit off colour but might just be from adjacent arcing. So my question is if ireplace theses components is it likely that it will fix the problem or are they just a part of a much bigger problem. any help much appreciated.

  • farmersgroup Mar 11, 2009

    I have the same problem. How can I find R184? Thanks Dave.

  • Anonymous Mar 19, 2009

    what is the value of R115 please?



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It is going into protect mode. It is a common problem, but is not an easy problem to fix. It will go into protect for 3 main reasons. I work at an authorized Denon service center and have repaired many of these models, so I know what I am telling you is correct.

Reason 1

The receiver has a blown channel. This will require the replacement of many parts. The output transistors, supply resistors, driver transistors, and a capacitor in the driver circuit of the affected channel. It is usually the channel that is located closest to the display board on the main heat sink.

Reason 2

A bad voltage regulator in the power supply. It has several voltage regulators all on their own small heat sinks. It is usually ref # IC101 or ref # IC102.
IC101 is a positive 15 volt regulator and IC102 is a negative 15 volt regulator. More often than not, it is the negative regulator that has gone bad.

Reason 3

The amplifier circuit has a 10 ohm resistor that supplies a high voltage to it and that resistor opens up and must be replaced. It is ref # R184. It is a 10 ohm 1 watt resistor.

Those are the 3 main reasons for your problem. It is not an easy unit to fix, but it is well worth the cost of a repair considering how much these receivers cost to purchase a new one. If you do not have the proper tools to fix this unit, please do yourself a favor and have a service center fix it for you. You will need a multimeter, soldering iron, solder, solder wick, and a # 2 phillips screwdriver. You will also need to isolate whcih of these 3 problems is causing the unit to go into protect. If you have a multimeter I can help you with it, but you still need the soldering equipment and must be skilled at using it.

Let me know if you require more help,


Posted on Oct 28, 2008

  • RJ Brossart
    RJ Brossart Jun 10, 2017

    Hi Dave. I have a similar problem with a Denon AVR-889 that I picked up for cheap on Kijiji. I replaced the blown transistor D2560 but I think the 7815 voltage regulators are reading quite high voltages. The 7815 VR's are IC801 and IC803 are both reading 42V in and 27.9 Should I replace both of these, or should I follow further upline to see what else might be causign the issues. It would be great to get this working again....keep this from becoming more e-waste in the landfill. Any thoughts would be greatly appreciated.



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