Hello, I apologize for my English, I write from Italy, I assembled two kits K8081, during the trial of one of the two I accidentally connected the amplifier to the input signal without connecting the speaker, it is charred resistance R4 and R43 and R42 are broken, also went short TIP142 and TIP147. I replaced all the transistors and all diodes and resistors R3 R4 R16 R17 R43 R42. Unfortunately, when I connect the power amplifier produces a breath and does not work properly. I have to replace other components, I have other controls ?
Using the amplifier without a speaker connected should never be a problem with a transistorized amplifier. I think you have another problem too.
It is almost impossible to destroy R4 because that would need almost the full 40 volts on it and there is no direct path to these 40 Volts … Strange. I would have thorough look at the soldering site of your PCB and check for short circuits.
the amplifier after the first assembly work properly but it was in standby after 15 minutes even with the audio signal, the problem occurred when checking the welds with the circuit out of the aluminum housing.
Did you power the amp while the output transistors were not connected to the heatsink?
That could explain the problem.
Anyway, in such a case, we recommend to simply replace all semiconductors (transistors and diodes) in the audio path.
Omitting one transistor can cause all the others to blow again, so the quickest and easiest way is to simply replace all of them.
They are commonly available and quite cheap.
I have replaced all but the semiconductor amplifier produces a very high background noise.
would be possible to have a new pcb to assemble all the components again ? I’m not sure that we have problems on capacitors and resistors.
Or should I have the wiring diagram provided with the tensions.
thanks
If this is possible, I prefer to order a new PCB and repeat the assembly of the amplifier, replacing all components. Would also be possible to order parts in bulk or have to think about this on my own?
tahnks
I understand you do not sell DIRECTLY, but I wanted to know if I can order from the distributor even electronic components or not.
You can repeat the code of the PCB? my dealer does not recognize the code P8081’1.
thanks
I contacted the supplier in Italy (FUTURA ELETTRONICA) and told me that they can not take the circuit board. I know indicate another supplier from which to request the PCB?
thanks