Omg, what have you done with the board, it looks like you have bitten the edge. What you should check is if there is the ac voltage at the primary side of the little transformer, but you need a device that can measure ac voltages with a high frequency, the best would be a oscilloscope. You can...

The Multimeter is to test the polarity on the connector of the power supply. I think it was false, and. Then 10a are a problem, because the transistors only can take 3a, but only in the right direction. I think the transistors should be changed and with a little luck there is nothing else...

10A power supply is very much, but no problem if your P20 is ok. Are you sure that you have used the right polarity? Did you have a multimeter? If you are lucky, only the both transistors are blown, and not the transformer. I think you should change them and test.

OMG I think you changed polarity or the power supply had more than 12V. Can you make a. Picture from the smoked area. There are two voltage regulators, they can be changed if burned, but if the little transformer is burned your Amp couldn't be repaired., because you won't find data to the...

I measured that the 115V for the heater also only has 111V, the ac for the 18V only has 34,5V and both DC. Voltages have 15,64V instead 18V. The circuit in front of the transformer oscillates with 45 kHz. The quistion is if these voltages are. Critical and part of the main problem.

The both electrolyte capacitors have 670yf an 640yf, I think that's OK for 680yf caps. Am I right that from the 12v DC would made a oscillating circuit that feed the little transformer with ac that has two outputs. These outputs use one diode and the 680yf cap to do the 18v dc in positive and...

I am at work, but at the weekend I will look for a revision on the Board. I located the area where the relays will be switched from. It is the section with the transistors over the cpu. The both ones in the middle of the transistor network are connected to the ones in front of the relays...

OK, i will try if the other relay works by switching between balanced and unbalanced. Am I right that boths relays will bei driven by the chip behind the volume knob? EDIT: I switched back and force between both inputs and outputs and in no case one of the relays got 12V on the coil, it is...

Thx for the answer, the one relay behind the xlr connector has gnd and 12V, so it seems so that it is switched. The other relay behind the led screen has 12V and 11,9V on the Input, so it can't switch. I'm not sure where the relays are for, one for switching between balanced and unbalanced and...

Hello, I'reading for some time in headfy org, but never postet something till now. I also own two P20 and one of it stopped working from one day to the other. I can switch it on but there is no sound, balanced or unbalanced inputs and outputs. On the working one there is a short click after...