One final check. Using the Diode function get readings on Q10 measuring from ground to the emitter, base and collector.

 

One final check. Using the Diode function get readings on Q10 measuring from ground to the emitter, base and collector.

Base 705 emitter 1.139 collector 511

 

OK. Turn on the amp and measure the Voltage on the emitter of Q10.

 

OK. Turn on the amp and measure the Voltage on the emitter of Q10.

if will stay on..

 

if will stay on..

E:11.7 B:46.9 C 13.00

 

I think you mean Base 13
Collector 46.9

 

I think you mean Base 13
Collector 46.9

no, has I said, I did check again

 

Anyway the -12 volt supply is OK. So I'm thinking the problem is on the mixer board.

 

Normally at this point with the mixer board disconnected I would test the audio output amps by injecting an audio signal to their inputs. You probably don't have this piece of equipment but usually can jury rig something using the headphone output of a phone or battery operated radio. We can discuss this when you have time.

 

Normally at this point with the mixer board disconnected I would test the audio output amps by injecting an audio signal to their inputs. You probably don't have this piece of equipment but usually can jury rig something using the headphone output of a phone or battery operated radio. We can discuss this when you have time.

Hi bro! Sorry for today, I get an important call from the vet, I have to answer, I have been on the phone for too long and I manage to be late for work, so I have to rush! Apology for not answer. I found out this: I did start it (couldn't resist) and it didn’t burn the R2! I have been able to play music! (so the amp output work, both) But then I do realise that I didn’t attach the little board that is connected to the J8, as soon I did attach it, after starting, I saw smoke close to the leg of Q10, I did disconnect it very quickly, as result i'm not sure were this smock was coming from! I did detach it from the board again (the little board) and it is “working” (look like/kind of) Is tay on and it play music...Now why is "working" without that small board? What is this board for? I'm apology for my ignorance but I'm usually fix television phone etc (and I should continue to do so) so I'm not familiar with amplifier... This little board is not on the schematic! This perhaps eliminate the mixer as faulty candidate? I thinking that is this board that make the problem, or something relate to it. Do you have any idea what is this board for? Thank you

 

You are exactly correct that's where the problem is. Will need to research that board.
Can you get some better photos

 

You are exactly correct that's where the problem is. Will need to research that board.
Can you get some better photos

Hello! here is the pictures you asked

 

Hello! here is the pictures you asked

I notice that on the schematic, there are 6 IC (TL072) but on the board I have only 4! so you were right when you said that this schematic it's not for the plus. (or this board is not the plus, (but on the amp it's say plus) Anyway, I checked many resistor in the little board, but I can't find anything. More than the little board faulty, I suspect something relate to it on the main board, the "only" direct connection with TDA, (the TDA was the cause of all this i thing) I see here, is on pin 7 which is connect to pin 3 at the TDA, checked many component around there but nothing obvious.....

 

Thanks for the photos. Have company over this weekend, can get back to it Monday morning.

 

postscript: Thanks for pictures!!!

Hi, I was wandering if you could help, do you know what is the small board connected on J8? Did you fix yours?

 

Thanks for the photos. Have company over this weekend, can get back to it Monday morning.

Ok, no problem speak to you Monday tho. Have nice day

 

I didn't fix yet, i'm too busy. We must to ask producer about small board, I'm curious too. Regards

 

Good afternoon. Are we ready to continue?

 

Good afternoon. Are we ready to continue?

Hi, good morning! yes bro thank you

 

OK, so right now the amp is working with that small board removed correct?