A 9010 o n k y o amp , schematics & help please

[zen]

Hi all

This amp has no audio .

Output transistors check out good .

No DC getting to speaker terminals .

80 V measured across bridge rectifier D 901 , therefore assume the + & - 40 V also present .

+ & - 12 V supplies at I C 01 & I C 02 respectively , also present .

No speaker protection relays on this model .

Audio present when taken from line out port , then through another amp , therefore assume at least part of the
p r e amp circuitry is working , depending on circuit layout .

[budwich]

Re: A 9010 o n k y o amp , schematics & help please

is there sound at the headphone jack?
hopefully the attached will help.

[zen]

Re: A 9010 o n k y o amp , schematics & help please

Hi & thanks

No audio via headphones .

Checked pins at CONNECTOR 07 , which is a ribbon type from main to front panel .

Not sure how to extrapolate some of the reading . Maybe someone could help .

THERMAL - P = 2.7 V

P - FAIL = 3.2 V

D 12 V = SLIGHTLY HIGH AT 15 V

DC 3.3 V = OK

VOL - LATCH = 2.7 V ALWAYS , REGARDLESS OF VOLUME ADJUSTMENT .

V PROTECT = 0 V

I PROTECT = 0 V

HP - DETECT = 0 V WITHOUT HEADPHONES CONNECTED & 3.2 V , WITH HEADPHONES IN

S P K A - R L = STANDBY 3.3 V , ON = 0 V

P - MUTE = 3.2 V

F - LATCH = 3.3 V

LINE 5 - L = APPROXIMATELY 2 VOLTS PEAK TO PEAK AUDIO SIGNAL . AMPLITUDE DOESN'T ALTER WITH VOLUME ADJUSTMENT .

LINE 5 -R = SAME AS ABOVE .

Note LINE 5 port is at front of unit , therefore i'm scoping audio from front unit coming back onto the main board .

HP MUTE = MINUS 10.8 V regardless of whether headphones connected or not .

A - MUTE = PLUS 4.2 V IN STANDBY , MINUS 10.8 V WITH UNIT ON

VOL - DATA = 2.7 V , but nothing via scope , except a slight jump if source changed

VOL - CLOCK = same as above .

SIGNAL - DETECT = VARIES 1.6 V TO 2.3 V

[zen]

Re: A 9010 o n k y o amp , schematics & help please

Not sure why i tried this but glad i did .

Disconnected the volume control board , powered on and now have audio .

Might be control itself , or one of the surface mount components on the underside .

[petehall347]

Re: A 9010 o n k y o amp , schematics & help please

strange as it seems maybe input selector ic fault .
i say this as had same thing a few years back with a similar amp .
hot swapping inputs can blow up the ic . well not visibly blown .

[zens electronics]

Re: A 9010 o n k y o amp , schematics & help please

Hi , thanks

That's IC04 & i did check , but seems ok .

I suspect it may be that useless grease that's used within the volume encoders.

Had it before on other units , but never like this , with no volume at all.

Will strip it down tomorrow & give it a clean .

[budwich]

Re: A 9010 o n k y o amp , schematics & help please

not knowing much past my recent learning around my onkyo 919, but also from general electronics travels, I would say you have a "shut down" issue (thermal) based on the "high" outputs of the two fail lines. I would trace back those areas to see where that gets triggered to be set.

a "quick look" of the schematics appear to indicate IC181 and IC182 are "thermal detectors" of sorts which can set the "protect high". They may be bad or otherwise.

[zen]

Re: A 9010 o n k y o amp , schematics & help please

Hi & thanks again for your input .

Unit is not going into protect mode .

With volume board disconnected unit works fine , which should mean all amplification stages good .

I will focus on the volume board for now , then update .Obviously the volume level is set , with PCB out of circuit .

I try to keep an open mind with these sorts of repairs , as i have been caught out so many times .

Regards Zen

[budwich]

Re: A 9010 o n k y o amp , schematics & help please

I see by looking further at the temp sensors that they aren't "binary" but are analog outputs which indicates they are fine and the unit is not in protection. sorry for the "misdirection". More looking and less posting... :-)

[zen]

Re: A 9010 o n k y o amp , schematics & help please

Yes your correct .

Stripped volume control , which is analogue type , to clean track , but same results .

Checked all surface mount components on audio board , but found no issues .

If i disconnect the volume in on pin 4 of connector on audio board , sound returns , obviously set to one level .

I'm now convinced there's a logic issue on the front board somewhere .

Also notice a small non volatile memory chip , & wondering if data has corrupted .

Also with volume module disconnected , if i try to measure or scope volume in test point on front board , the sound level reduce to zero .

Also reset unit to default settings with following procedure , but same results .

While the unit is on, press and hold the DIRECT button
and press the ON/STANDBY button.

[budwich]

Re: A 9010 o n k y o amp , schematics & help please

OK.... the "volume test" sequence is a good idea / result. On the pin 4 in the board, do a resistance measurement (to ground)... maybe all you have is a shorted cap or maybe the other way around (open cap)... looking at the circuit. :-)

[zen]

Re: A 9010 o n k y o amp , schematics & help please

No , unfortunately not a low reading to ground issue .

On the VOLUME IN line only one cap , which i have checked & one 33 OHM resistor , before line goes to pin 52 of main micro .

Regards caps on the audio board , i have checked them all .

[budwich]

Re: A 9010 o n k y o amp , schematics & help please

:-( not necessarily looking for a low reading to ground... looking for some impedance value to compare to as there are resistors in the path. Does the reading make sense?
Further, does the reading change as you change the volume control?

[budwich]

Re: A 9010 o n k y o amp , schematics & help please

I think we are talking "two ways"... :-) I was referring to the volume board pin 4 while you were referring to the MCU board pin 4. Measuring toward the micro doesn't give you much other than a good feeling that there is some impedance and not open circuit / grounded. I would think measuring at the volume board to see if you are getting valid impedances / response from the board. Again, just my read.

Based on your disconnecting the pin 4 at the MCU getting sound, would appear to indicate a volume control / feed problem. Hope it helps and is not "sideways" again. :-)

[redwire]

Re: A 9010 o n k y o amp , schematics & help please

The volume control seems to be an analog control voltage 0-3.3V from the motorized potentiometer, then fed to the MCU A/D converter VOLUME_IN. Then the MCU sends digital volume SPI to IC04, IC05.

[zens electronics]

Re: A 9010 o n k y o amp , schematics & help please

Hi , yes IC04 & IC05 both connected to the data bus .

Both chips seems to operate well , with volume board disconnected .

I can select any of the line inputs and audio goes through ok .

Do have a slight suspision that data within SPI chip might be corrupted.

[redwire]

Re: A 9010 o n k y o amp , schematics & help please

What does the receiver (MCU) do with the IR remote control volume up/down?
I guess it just commands the potentiometer motor to move up/down.

With the volume board disconnected, I just see the MCU A/D input floating and picking up noise.
That just leaves the potentiometer's output voltage VOLTAGE-IN pin4 stuck at zero or something. Or the IR rx module is spitting out noisy packets confusing the MCU.

[zen]

Re: A 9010 o n k y o amp , schematics & help please

That's a good point , thanks .

I don't have remote control at workshop , but can get customer to pop it in .

I could even remove the IR receiver to prove a point .

Regards Zen

[zen]

Re: A 9010 o n k y o amp , schematics & help please

Can anyone help with UK spares contact details for this company ?

[budwich]

Re: A 9010 o n k y o amp , schematics & help please

No , unfortunately not a low reading to ground issue .

On the VOLUME IN line only one cap , which i have checked & one 33 OHM resistor , before line goes to pin 52 of main micro .

Regards caps on the audio board , i have checked them all .

did you look in the other direction? toward the volume board? You should check to see if the board it "outputting" something in response to volume changes.