Denon avr 2802 with no sound on speaker

[tufi979]

Re: Denon avr 2802 with no sound on speaker

Yes , I downloaded it.

I would test it like this:
1. Check the voltages and ripple of the voltages that supply all the chips the signal goes through
2. Apply a sine wave signal from a function generator (could be from a PC or cellphone) on any of the inputs and then follow the signal through the circuit and see where it gets lost.

I'm afraid without a scope that will be next to impossible.

I aplied sine wave 500hz to dvd input and folowed signal to pin 24 and 5 (left and right ch ) and that is where signal stops. When i baypass signal from pin 24 to 26 i get sound on speaker left or right depends which one i baypass 24 for left an 5 for right. In this case i dont have volume control i cant turn volume up or down i mean there is no diference in output sound no matter if volume gors up or down. I guess in this way i baypas volume control . So it must be master ucom or something else that is between those two ???

[tufi979]

Re: Denon avr 2802 with no sound on speaker

I get this signal trace only in direct and stereo mode , in every other mode there is no signal on those pins, could it be DA converter IC 602 also ? because there is no signal output on pins 23 till 28 this is signal for rest of the channels except front ones.

[paulstef]

Re: Denon avr 2802 with no sound on speaker

Would be interesting to know if IC809 works, it uses the same DATA and CLK input just a different strobe input. Anyway you could try this with your 500Hz signal?

Any shorts on DATA or CLK or STB? A logic analyser would come in handy

[tufi979]

Re: Denon avr 2802 with no sound on speaker

i tried this signal to trace on IC809 but no output signal and as i can see STB4 is from function selector ? right ? I think this is volum control flow:, from knob to IC303 then to ic 809. I would check for shorts tomorow

[paulstef]

Re: Denon avr 2802 with no sound on speaker

i tried this signal to trace on IC809 but no output signal and as i can see STB4 is from function selector ? right ? I think this is volum control flow:, from knob to IC303 then to ic 809. I would check for shorts tomorow

From what I understand when the strobe input is activated the chip will use the bits that arrived in the input register right before that. Much like a chip select, only after transmission. This means you can drive several chips with the same data line and only activate the strobe for the chip that's supposed to receive that message.

page 5 : http://pdf1.alldatasheet.com/datashe...BA/TC9459.html

[tufi979]

Re: Denon avr 2802 with no sound on speaker

You think that this is the best part to change and to see what will happen? or maybe will be better idea to find some oscilloscope to verify signals. What do you think it is the enough range for oscilloscope 20Mhz for audio service ? I will not use it to much for servicing that i do i rarely need oscilloscope i dont want to throw money away
So you think that i should check if clock is change on input pin of IC 805 when volume is going up or down and if there is change IC 805 is bad , and if it is not changeling then something before is wrong? right ? Or do you have better approach?

[tufi979]

Re: Denon avr 2802 with no sound on speaker

My friend will bring me his oscilloscope tomoro evening tell me what to check , where, and what readings to expect ?

[paulstef]

Re: Denon avr 2802 with no sound on speaker

A 20MHz scope will do. Max clock frequency for these chips is 1MHz according to datasheet.

Check Clock, Data and Strobe line of the volume chip. You must refer to the datasheet I posted to understand the signals. It will take you at least 2 scope channels.

[tufi979]

Re: Denon avr 2802 with no sound on speaker

Update: i cleaned all connectors and resoldered all chips but
Unfortunately this didn't help i tried that and same problem exist. Very low sound on max volume only in direct mode and as soon you change mode or input source sound stops and is no longer present ,when you switch it back to direct no sound until, switch of and switch back on. Any more ideas ? I will check tonight with oscilloscope for clock on all chips.

[sparx_59]

Re: Denon avr 2802 with no sound on speaker

Hi guys,
Old topic, I know , but still I want to let you know I fixed it today.
I was able to flash some new chips and replace them on the DSP board.
Until now I fixed my 2 receivers, and I am willing to share it.
Please feel free to contact me.

Henk

[sparx_59]

Re: Denon avr 2802 with no sound on speaker

To be complete: The problem is the IC817. This is a flash chip wich holds the data for the DSP uprocessor. This chip will sometimes fail. The data is still in it, but the processor has problems reading it due to wear. In other words: the chip is getting old. I was lucky enough to be able to read the data from a faulty chip with a programmer. Flashing this data in a freash chip resulted in a fully working rom. I had replaced two boards with these chips, and this fixed the problem. I know Denon does not support the avr 2802 anymore, so I want to share the fix to help ppl with this problem. Please feel free to ask any question! I am happy to answer them.

[Agent24]

Re: Denon avr 2802 with no sound on speaker

That's great to hear! I'm sure people would be very grateful if you were to upload the firmware image here or somewhere like Elektrotanya

[sparx_59]

Re: Denon avr 2802 with no sound on speaker

Here you go
https://www.dropbox.com/s/fcembdd9eq...02%20dump?dl=0

Flash it on a new chip, solder it on the board, and ready!

[Chungalin]

Re: Denon avr 2802 with no sound on speaker

Congrats for the good job and thanks for sharing. I'll keep the file just in case I meet one of these.

[sparx_59]

Re: Denon avr 2802 with no sound on speaker

Congrats for the good job and thanks for sharing. I'll keep the file just in case I meet one of these.

De nada

[Chungalin]

Re: Denon avr 2802 with no sound on speaker

Actually, I already met one back in 2010. Symtptom was "no sound" (I deduct from my notes that everything else seemed OK) and I suspected that was something related to DSP board. I was unable to fix it and it was returned to customer without solution. What a shame...

[sparx_59]

Re: Denon avr 2802 with no sound on speaker

Yeah, 1st log I found was around 2007 and up.
Lots of denon's died after 5 or 6 years.
I really don't know why no one copied the rom before.
Probably because they had to remove the rom from a working board.
I just took a shot at it, by copiying a rom witch dump looked ok.
It could not have been an accindental overwrite of data, because the write enable is pulled up to the positive rail, so it had to be a bad readable rom. This also explains why the board worked sometimes and after turning a knob, it stopped working.
The Cpu is to fast in this case, but a programmer reads lots slower, and that solved my problem. Sad thing is very few ppl read the old posts where they talk about the problem. So here I am with a fix for a really great receiver, and I cannot help, because it took to damn long

[Chungalin]

Re: Denon avr 2802 with no sound on speaker

Is it an Atmel AT49LV002-70TC ? Is it still available or do you use an equivalent?

[sparx_59]

Re: Denon avr 2802 with no sound on speaker

I use the exact same chip. They are still available.

[Chungalin]

Re: Denon avr 2802 with no sound on speaker

I’ve never programmed a parallel Flash Memory (TSOP), only serial EEPROM. What kind of programmer do you use?