powered sub wont come out of standby

[budm]

Re: powered sub wont come out of standby

I do not know why everyone focused on the relay... in the first post it is said that "the led started flickering between green (active) and red (standby) now just stays red" we should get the green led again and then if the issue persists check the relay.

So do the heating test first, then change all caps... or just skip the test and change the caps. At least this is what I would do if had to work blind ( without checking the V lines )

1) We do not know what the relay contacts are connected to, output of the power amp to the speaker/
2) we now know that the relay clicks but is the contact actually closed and conducting.
3)OP indicated the Voltage outputs are correct but I did not look at the power supply section in details yet to have OP verify the reading., and need to find out of the output Voltages fluctuate in sync with the blinking LEDs or not.

[moss99]

Re: powered sub wont come out of standby

Ok , a bit strange , i was just looking at the voltages again and heard the relay click and the led turned green , i also noticed the transistors on the power board are getting quite hot so i powered off . i turned it on again led was red , i dont know if it was coincidence but i wiggled the power lead in its socket ,the relay clicked and green light again .
But i cant recreate it by moving the power lead now , i just have red led again .

[madan1]

Re: powered sub wont come out of standby

bad solder joints... interrupted paths... corroded connectors... bad cables.. not many things can be affected by applied force.

[moss99]

Re: powered sub wont come out of standby

Hi , i have taken this cap out (circled in red ,in photo) and have an ESR reading of 0 , its a 1000 uf 25 v

[budm]

Re: powered sub wont come out of standby

Are you able to get the rest of the diagrams?

[budm]

Re: powered sub wont come out of standby

Hi , i have taken this cap out (circled in red ,in photo) and have an ESR reading of 0 , its a 1000 uf 25 v

What is the P/N of the device with 3 legs right next to the cap?
What DCV do you get between the two legs of that cap?

[madan1]

Re: powered sub wont come out of standby

1) We do not know what the relay contacts are connected to...

well... on the photos we see two transformers, so most likely one is for the stand-by curcuit, the other one is for the power amp. From what Ive seen on other units, I guess the relay cuts the power of the big transformer.

Also since the LED always stays on ( red or green ), then its curcuit must be powered from the stand-by.
The problem affects the LED behaviour, so it should be something on the stand-by curcuit.... at least that's my logic.
If we had peoperly operating LED, but no sound, then I'd have started with the relay... now it is just pointless to play with it and as already noted - can cause further damage.
Without the schematics, at least few good photos or voltage readings, that's the way I'd proceed

[budm]

Re: powered sub wont come out of standby

Well, post 14 OP indicated the Voltages on the power supply board are correct:

Ah , no sorry my bad , i had my negative tester lead on the AC ground , the voltages at J5 , J6 and J7 are all correct at the output board . also i can hear the relay click when i shut off the power .

So the power supplies are on and the relay is also ON but we do not know if the contacts are actually closed or not.
We will know more when we get the rest of the schematic.

2) we now know that the relay clicks but is the contact actually closed and conducting?.
If you look at the power supply schematic AW-12 power v2, you will see the large transformer T1 is getting the B+ to run from the two main filter caps C21, C22, that B+ is also used for running the transformer T3 driven by IC U6.
The large T1 for the SMPS is turned on by the STANDBY command signal (This signal is active high and present when the unit detects incoming audio signal) which turns on OPTO U4, and the switched Transistor Q3 which supplies the VCC to PWM IC CW6805 which drive the Gate drive transformer T2.
The relay on the power amp board is SPST, looking at the back side of the power amp board, it looks like the contacts are used for the speaker.
The relay in schematic RXW-12_Power_Non EUP_030909 is DPDT, so that is not the same relay and the schematic is not being used for this unit, same for the schematic RXW-12_Power_Non EUP_030909 (it does not have PFC circuit).
If you think the relay is being used to power the large transformer the contacts of the relay would have been in the hot (primary) side of the power supply but it is not, and the coil would have been in the cold side.
The small ALWAYS ON power supply (Transformer T3, SMPS IC U6) is for making the +/- VEE (from D10, D13) probably for running the OPAMPs.

[budm]

Re: powered sub wont come out of standby

OP can also look at the STANDBY command signal at connector CN3A pin 1 to see if it is present and steady or not. That CN3A should go to the preamp, and STANDBY control board board where the audio is fed into.

[moss99]

Re: powered sub wont come out of standby

Hi , this is the reply i got from them regarding the rest of the schematics " Unfortunately we don’t. Everything I sent you before is all we have. Some of the suppliers we used to use for our amps were not very forthcoming with the supply of circuit diagrams. Sorry ..

so i guess they buy the boards in and assemble them . the device next to the the cap is : L7812CV 640RG V6 CHN 047 . There is 15 v DC between the cap pins , is the 0 ESR reading not a cause for concern ? i have also got another relay ,.

The relay is no longer clicking when i shut off the power , i think possibly i heard it click a few times when the led must have been green ,
So if the led stays red when powered off no relay click .

[budm]

Re: powered sub wont come out of standby

Hi , this is the reply i got from them regarding the rest of the schematics " Unfortunately we don't. Everything I sent you before is all we have. Some of the suppliers we used to use for our amps were not very forthcoming with the supply of circuit diagrams. Sorry ..

so i guess they buy the boards in and assemble them . the device next to the the cap is : L7812CV 640RG V6 CHN 047 . There is 15 v DC between the cap pins , is the 0 ESR reading not a cause for concern ? i have also got another relay ,.

The relay is no longer clicking when i shut off the power , i think possibly i heard it click a few times when the led must have been green ,
So if the led stays red when powered off no relay click .

L7812CV is just a 12V Linear regulator soa s long as the output is 12V then you are fine.

[budm]

Re: powered sub wont come out of standby

OP can also look at the STANDBY command signal at connector CN3A pin 1 to see if it is present and steady or not. That CN3A should go to the preamp, and STANDBY control board board where the audio is fed into.

So check that STANDBY command signal, you may need to have audio input to get the unit out of standby mode.

[moss99]

Re: powered sub wont come out of standby

These are the voltages on CN3A not sure which is 1 ..
Im using the - pin of the large capacitor on the output board for the negative probe on my meter , is that ok ?

[budm]

Re: powered sub wont come out of standby

OK,
Top pin is pin 1 (STANDBY) = 7V so command signal to turn on the main SMPS is present.
Second pin down is pin 2 (+VEE) = 8V, OK
Third pin down is pin 3 (GND) = 0V , OK
Fourth pin down is pin 4 (-VEE) = 8.7v, OK (close enough)
And since you did report that you checked the DC outputs of the power supply and they are correct so at this point the power supplies are OK, and the STANDBY controller is working.
So something is not turning on the relay to turn, so you need to verify if you do have 12VDC on the relay coil or not.
But something is still not clear is that the STANDBY command signal is present to turn on the main power supply but the LED stays RED.

Can you take good and super clear straight shot pictures of the Audio input board top and bottom sides?

[budm]

Re: powered sub wont come out of standby

BTW, can you tell us how the speaker is connected to the amp board and which connector?
The more pictures the better.

[moss99]

Re: powered sub wont come out of standby

these are the relay volts , the speaker cables are soldered in , see photo .

[moss99]

Re: powered sub wont come out of standby

power board top / bottom

[budm]

Re: powered sub wont come out of standby

So the relay is speaker protection relay.
The two terminals of the relay that show 0 VDC are the relay coil, so right now the relay is not energized, but just to be sure, what did you use for the meter GND?

[moss99]

Re: powered sub wont come out of standby

the negative pin of C42 (see pic)

[budm]

Re: powered sub wont come out of standby

I do not know for sure if that junction connection between the two caps is the circuit GND or not, but if it is circuit GND then the amp output has dc offset of 8.8VDC, that means the protection relay will not come on. I wish we have the schematic of that power amp and the input board.