Audiolab 8000A Fault

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Hi,

After 14 years of loyal service, my Audiolab 8000a has just developed a fault. :bawling: I get a constant 'thin' output from the left channel regardless of volume or balance control position. Defeating the tone controls also makes no difference. I've also connected the pre-amp output to another power amp and the fault is still there so it looks like the problem is with the pre-amp stage. Also I've connected the 'record' output from one of the tape recorders inputs to another amplifier and this works OK, so the fault lies between the record output stage and the pre-amp output stage. Can anyone help or does anyone have a circuit diagram / PCB layout drawing for one of these amps ?

Many Thanks
 
My Audiolab 8000A has just developed a fault. I get a constant low output from the volume control position. I've control the volume with the remote control of the CD source. So, one day, some components of the circuit burned and no tecnical support are avaiabla because the constructor is out. The burned components are so black that's impossible see the values, for eventually replace it. Can anyone help or does anyone have a circuit diagram / PCB layout drawing for one of these amps ?
 
About the burned components, I can't read the values off the same part in the other channel, I can't find the "twin" components. I think they are be pretty generic, and the location is near from the power supply. Exactly between the channels and the power supply. Some of they are a resistor or resistence.
 
Audiolab 8000A fault

Hi,

I have news about my problem. So, the burned componets seem to belong to a one of the channels, but it's not easy to find the same in the other channel because the disposition of the components is different. One of these looks like a diode in the diagram of Steven, but in the circuit it is a resistor. (?)

Thanks, specially mikers & Dr. Photon.
 

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Audiolab 8000A problem

Hello everybody,

I just bought a used Audiolab 8000A amp. After unpoacking it appeared that the right channel always gives a very low output, regardless of the volume. I also connected another amp to the pre-amp output with the same result.
On the board no noticeble damage is present. What could have happened, does anyone know if the 8000A has any internal fuses that could have blown.
I found the same problem in another thread, but no solution was given.
Thank you very much.
 
Hi,
I wonder if it is a broken volume control?
Try connecting to tape out to hear/measure if the signals match.
try connecting your input to a different input RCA, again comparing at the pre-amp outputs and tape outputs.

As you can see, with a two channel multi-input/output you have a lot of options to find bits that work and try to home in on the bits that don't.
 
I tried to connect the pre-amp output to another amplifier and it gives the same problem: The right channel is giving a very low, "thin" signal, that hardly responds to the volume control.
The left signal is perfectly ok.
What could it be? A broken volume control would affect both channel, wouldn't it?

Thanks

Wouter
 
I'm sorry. I posted the other posts, because I couldn'd find my previous posts and thought something went wrong.
Now I see that to start a new thread first a moderator has to approve it.

Regards and sorry for the inconveniences.

Wouter
 
Thank you for your reply Andrew.
I tried the other input RCAs, but still the same.
Tape out is ok, but that's only a bridge between the input RCA and tape out, isn't it.
It should be in the pre-amp part of the circuit doesn't it?
Any other suggestions?

Thanks a lot

Wouter
 
You're getting closer.
You now know that the fault is not in the RCA inputs nor in the circuitry upto the tape outs.
You also know it is before the power amp and before the pre- out tappings.
The fault is in the section between tape out and pre-out.

It could be a faulty volume control (one channel cracked or open circuit) or a faulty/cracked PCB trace, or a faulty soldered joint, or a faulty active component.
I think it is unlikely to be a faulty passive component, but others with more experience may disagree.
 
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