Hello, everyone ,
Here again , with a new repair
Well, the first thing I've seen, when you open the lid, (it's all perfect , no one has touched anything ) is , like you have entered some kind of liquid into the amplifier , ( the plastic of the three leds, had oily debris ....) and also , in a corner of the chassis, where it has the screw hole , I also appreciated dried remnants of fluids , and corrosion ¿,,?
That has been , at first sight, when I connected , blue LED lit , as well , but very weakly , (almost not lit) LED orange protective ...
Connected audio input , a music signal , (MP3 )
When connecting the speaker to the front channels are silent , without the slightest sound of any kind ....
In the rear channels : on the left, with the gain level to near maximum , we must bring the ear to hear very little sound.
In law, great leap of the speaker cone , of course ! , I measured with the multimeter , and there is 24.42 volts ....
In the other channels , no appreciable voltage .
I have checked all the output MOSFET , and have not found any short or open , too, all the drivers that are below the mosfet , and I have not found one in poor condition.
Any clue of where to keep looking ?
Here again , with a new repair
Well, the first thing I've seen, when you open the lid, (it's all perfect , no one has touched anything ) is , like you have entered some kind of liquid into the amplifier , ( the plastic of the three leds, had oily debris ....) and also , in a corner of the chassis, where it has the screw hole , I also appreciated dried remnants of fluids , and corrosion ¿,,?
That has been , at first sight, when I connected , blue LED lit , as well , but very weakly , (almost not lit) LED orange protective ...
Connected audio input , a music signal , (MP3 )
When connecting the speaker to the front channels are silent , without the slightest sound of any kind ....
In the rear channels : on the left, with the gain level to near maximum , we must bring the ear to hear very little sound.
In law, great leap of the speaker cone , of course ! , I measured with the multimeter , and there is 24.42 volts ....
In the other channels , no appreciable voltage .
I have checked all the output MOSFET , and have not found any short or open , too, all the drivers that are below the mosfet , and I have not found one in poor condition.
Any clue of where to keep looking ?
Attachments
I connected the bridge, as you have told me, (for ten minutes) but is not seen no change, does not heat anything, nor is there excessive consumption ..
The other channels are still not working, (dumb) despite having an audio signal present at the input, and the level of gain near maximum .....
weird?
Note: I have not installed the output MOSFET.
The other channels are still not working, (dumb) despite having an audio signal present at the input, and the level of gain near maximum .....
weird?
Note: I have not installed the output MOSFET.
Attachments
I have checked the transistor, but I have not found evidence that has a short or is open ....
He contrasted the values I have taken that transistor, with the values of the same transistor side plate, and there is a minimal difference (more or less than 0.20 ..)
I have checked the values of other transistors, with the plate next, and I found few differences ...
Yes, I found Q204 (labeled 2A) has a short between the base and the collector, and to check on other plates, also in short ... is this normal?
He contrasted the values I have taken that transistor, with the values of the same transistor side plate, and there is a minimal difference (more or less than 0.20 ..)
I have checked the values of other transistors, with the plate next, and I found few differences ...
Yes, I found Q204 (labeled 2A) has a short between the base and the collector, and to check on other plates, also in short ... is this normal?
I unsoldered the collector of Q204, to check if he was really short, but no, the transistor is well, then, I have contrasted with a new one that I have in my closet, and its measurement is correct ...
I have reinstalled the output MOSFET .... I reconnected, now at least, are no longer present the 24.40 volt output was in the rear right channel audio ... there is only: 2.94 volts .....
I'm lost ....
I have reinstalled the output MOSFET .... I reconnected, now at least, are no longer present the 24.40 volt output was in the rear right channel audio ... there is only: 2.94 volts .....
I'm lost ....
Attachments
Well, I checked all resistors AB card right rear channel output, and have contrasted with the other three cards of the other three audio channels, and these are the results:
In almost all resistance measurements, the differences with their counterparts in the other cards were very minimal ...
Except ..., R206 has given me a value of 211 kilohms, and in the other three cards, its real value is 212 kilohms
And also, and this I found most odd, R202 (is located above the drawing of the parrot) starting value of 1.7 kilohms beginning to rise to 4.0 kilohms, and from there, to jump to the 19 or 20 kilohms .... being its value in the other cards, of 22.3 ohms
Is this normal?
In almost all resistance measurements, the differences with their counterparts in the other cards were very minimal ...
Except ..., R206 has given me a value of 211 kilohms, and in the other three cards, its real value is 212 kilohms
And also, and this I found most odd, R202 (is located above the drawing of the parrot) starting value of 1.7 kilohms beginning to rise to 4.0 kilohms, and from there, to jump to the 19 or 20 kilohms .... being its value in the other cards, of 22.3 ohms
Is this normal?
Well, I got the strength, and indeed, when measured outside the card had a value of 56 kilohms ....
I've replaced with a new one, I've also replaced the transistor that you said in post # 6 with a new ...
And to connect the amplifier, has left some smoke in the area of resistance, I took it out and indeed is almost open, scores 52 kilohms ...
Back again present 24.42 volts at the speaker output of that channel .... ¿...???
I've replaced with a new one, I've also replaced the transistor that you said in post # 6 with a new ...
And to connect the amplifier, has left some smoke in the area of resistance, I took it out and indeed is almost open, scores 52 kilohms ...
Back again present 24.42 volts at the speaker output of that channel .... ¿...???
Just remove a good a/b output card from the other amp and replace the card. You will be time and money ahead. I stock these cards new as well if you would like to get one PM me.
Sometimes you can spend hours trouble shooting a driver card but you can swap them out in 20 min.
Just a thought............
Sometimes you can spend hours trouble shooting a driver card but you can swap them out in 20 min.
Just a thought............
It appears that I can not find the defective part ... I extracted several pieces on suspicion of them (I gave rare measures when measured on the printed circuit ...) but to measure them out, they were good,,,
Which leads me to think that there may be some leaking or open driver ...
I'll talk to Sean by PM.
I have a question in my head: then, if the other three channels are supposed to be good, why not produce any audio sound clean? Does not the protection circuit blocks some channels are fine, when it detects a fault on the other channels?
Which leads me to think that there may be some leaking or open driver ...
I'll talk to Sean by PM.
I have a question in my head: then, if the other three channels are supposed to be good, why not produce any audio sound clean? Does not the protection circuit blocks some channels are fine, when it detects a fault on the other channels?
Well, I've already removed the card drivers, is about to reach me, I bought another amp to repair it, (P400-2) arrive tomorrow ... I think
Sean, you have not answered my PM ....., maybe you could not, well, anyway ... nothing happens.
Perry, do you think I should do some checking, being the card out of the motherboard?
Sean, you have not answered my PM ....., maybe you could not, well, anyway ... nothing happens.
Perry, do you think I should do some checking, being the card out of the motherboard?
Attachments
Yes, Perry, I have checked all the components of the driver board (resistors, transistors, diodes, capacitors smd ...) I returned to check them today, to make better, and I found an electrolytic capacitor with very low capacity. ... (see picture) is labeled with 10 microfarads,,, ( C202 )
I hoped that I got another amp that I mentioned to repair this one, but it has not come,, mmmhhm .... and already, I will not come until Tuesday, because here in Spain, there are two days of festivities ...
Sean, Q18 and Q19, I desolder the board to check them, and they're fine.
I know this may be difficult to repair, but will not give up ..
Thanks for the tips, I always appreciate your help.
I hoped that I got another amp that I mentioned to repair this one, but it has not come,, mmmhhm .... and already, I will not come until Tuesday, because here in Spain, there are two days of festivities ...
Sean, Q18 and Q19, I desolder the board to check them, and they're fine.
I know this may be difficult to repair, but will not give up ..
Thanks for the tips, I always appreciate your help.
Attachments
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