Denon AVR-X2000 Thermal B shutdown after few minutes

Dadafu

Novice Member
Hi,

So I bought this amp 5 years ago and it didn't moved of his place since. He is positionned in a open desktop with 6-7cm on the left and right, and 30cm top.
I don't use it often, about one to two times a month.
It has always been pretty hot (compared to my old Aiwa amp) when I touched it when it's powered on, with speakers connected or not, and I can smell a little odor of hot electronics, but i never worried, it was working correctly.
But yesterday, after ~30min of use, it turned off with the red light blinking slowly.
With the maintenance mode, I managed to display the error "prt:thermal B"
When I turn on immediately afer this, it turns off before I can hear the second relay.
If I let it cooldown a few minutes, it's working again during a few minutes.

It works OK with the protection pass mode, but i'm worried about to fry something now..
It works longer with the main cover removed. So I think we can deduce that something goes too hot.

I use the two front channels with one analogic input. All other outputs are disabled. I tried to use the ZONE2 with MAIN ZONE disabled (for trying other channels), but same problem.
I tried factory reset, updated firmware, but still the same

I got a multimeter and a infrared thermometer, the big heatsink goes to about 40°c-41°c, it doesn't seem much for me.. Buy I can feel the hot air flow. what do you think about ?
Here the service manual if someone can help me. (DENON AVR-E400 SERVICE MANUAL Pdf Download | ManualsLib)

Do anyone know where I can look or verify ? Thank you !
 
Last edited:

gibbsy

Moderator
Welcome to the Forum.

Five years of dust getting into the unit can cause overheating. I'm not going to tell you to take it apart as it's something that I would not contemplate doing and would take it to a repairer for a service.
 

Dadafu

Novice Member
Hi and thank you.

I've dusted it internally, unfortulately the same problem is still here

Yeah it doesn't look easy to take apart, but maybe I can check some parts with my multimeter or my finger if it is the temp?
 

Dadafu

Novice Member
Hello again,

I opened again the receiver, and I've put three 80mm fans directly on the big heatsink. It's cold as ice like this :p
I was ok during ~2h, until it turned off again, but this time, with fast red led blinking.
In the service menu, this time, it shows "prt : DC"
If I understand this, it seems to have a DC current in the output. I mesured 0.25v on the left and 0.28v on the right channel. Are these values seems good for you ? Thank's
 

gibbsy

Moderator
Hello again,

I opened again the receiver, and I've put three 80mm fans directly on the big heatsink. It's cold as ice like this :p
I was ok during ~2h, until it turned off again, but this time, with fast red led blinking.
In the service menu, this time, it shows "prt : DC"
If I understand this, it seems to have a DC current in the output. I mesured 0.25v on the left and 0.28v on the right channel. Are these values seems good for you ? Thank's
Too technical for me sorry.
 

kena999

Member
was just browsing the articles here....i have a suggestion....

take a look at page 125 of the service manual and enlarge the input circuit on the amplifier...

compare this to the input circuit on the dyna 150 attached...

the amp you have is relying on the two input transistors (differential input configuration) being very closely matched to achieve 0 volts DC offset at the output....if the protection circuit is looking for DC on the amp outputs, 28mV may trip it.

the dyna amp has a pot on the current mirror transistor Q3 that allows you to zero out the DC offset.....if you are real ambitious, you could emulate that by adding a pot in place of one of the two resistors (like R401) in the emitter line on that transistor (Q401 in your unit)...make the pot the same or a close value to the resistor you are replacing (1K in this case)....with a voltmeter attached to the output of the amp you will then be able to set the offset voltage to zero.....bear in mind that in order to satisfy the protection circuit, you may have to do this to each channel of the amp....there are three channels shown on page 125....im not sure how many channels there are on your unit....

it sounds like this may be within your skillset to do this, but anyone familiar with servicing could do this for you or show you what to do....always work with the power off of course...cheers!
 

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