What should I look into and fix?
The 2020 has no DC offset adjustment, however adjusting the Idle current generally brings down the offset. On each power amp circuit board there is a terminal pin (TP0) ate the very front that has nothing connected to it. Next to TP0 is either a brown or yellow wire on the next pin. Set input to an open circuit (Phono 2 is good) and volume to 0. DC volmeter across TP0 and yellow wire and adjust the variable resistor at the far end of the board to get a reading of 10 millivolts. Do the same on the other board between TP0 and the brown wire. See if that helps.
merrylandar, thanks so much for the guidance.
I removed the wood case and see relay on the left front PCB and the black output cooling fins (2) in the center section. Would you point where the "power amp circuit boards" are? Are the two PCBs sit between the cooling fins? If yes, please ignor the photo request below.
There is no Phono 2 input selection, just Phono. Set to Phono OK? Speak at A or None? Volume at 0?
Do you mean to measure VDC between TP0 and the yellow wire on one PCB; between TP0 and the brown wire on other PCB?
Anywhere I can find a photo to identify the location of these parts will be wonderful. I can do this task but just need locations so I won't mess up other things.
Thanks
There's a sticky topic at the top of this forum that explains measuring dc offset. Basically, you measure for dc voltage at the speaker outputs with the speaker switch set to the A speakers, input set to an unused input, volume at zero. let the receiver warm up for a few minutes, then measure. You should see a voltage like 0.02 vdc.
Bias setting is more involved, and will require access to a service manual.
Let us know what you get!
The 2020 has no DC offset adjustment, however adjusting the Idle current generally brings down the offset. On each power amp circuit board there is a terminal pin (TP0) ate the very front that has nothing connected to it. Next to TP0 is either a brown or yellow wire on the next pin. Set input to an open circuit (Phono 2 is good) and volume to 0. DC volmeter across TP0 and yellow wire and adjust the variable resistor at the far end of the board to get a reading of 10 millivolts. Do the same on the other board between TP0 and the brown wire. See if that helps.
With the power on what readings do you get between the chassis and either the yellow or brown wires noted above?