Denon avr 2802 with no sound on speaker

[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.

[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

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

[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?

[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

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

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 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.

[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 ???

[tibimakai]

Re: Denon avr 2802 with no sound on speaker

Usually, no sound is a badly soldered DTS chip, at least at other brands. Oven trick, may work for a while.

[paulstef]

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.

[tufi979]

Re: Denon avr 2802 with no sound on speaker

Do you have an oscilloscope?

Did you manage to download service manual that i uploaded ? is it ok ?

[goontron]

Re: Denon avr 2802 with no sound on speaker

Ha ha , did you had some "good " experience too

many...

[tufi979]

Re: Denon avr 2802 with no sound on speaker

i dont have osciloscope

[tufi979]

Re: Denon avr 2802 with no sound on speaker

Ahhh Denon, Run away!! sorry, had to.

Ha ha , did you had some "good " experience too

[tufi979]

Re: Denon avr 2802 with no sound on speaker

No

[goontron]

Re: Denon avr 2802 with no sound on speaker

Ahhh Denon, Run away!! sorry, had to.

[paulstef]

Re: Denon avr 2802 with no sound on speaker

Do you have an oscilloscope?

[tufi979]

Re: Denon avr 2802 with no sound on speaker

here is short version of service manual.

[paulstef]

Re: Denon avr 2802 with no sound on speaker

I only find it on eservice and it's chopped into 3Mb files...