When replaced, measure various parameters vs the not failed/repaired other negative section too. Of course -Vo first, but also mV drop across the 1Ω resistors (1mV=1mA) to see if all the led-bars are driven by the same mA CCS more or less, Vbe of the BJT transistors to see if all are still on, compare some spot voltages vs ground between the sections etc.
So, here is what I get after adjusting dc offset again a little.
A hum, which is more like electrostatic noise mixed with morse code. Music plays but very distorted, kike out of last breath. Cannot even increase volume as it is feels almost like clipping
A hum, which is more like electrostatic noise mixed with morse code. Music plays but very distorted, kike out of last breath. Cannot even increase volume as it is feels almost like clipping
I hope you did not compromise the TKD when you tried it on a loudspeaker output with a speaker as load. Do you have a cheap spare log pot to wire and compare? Before doing that connect RCA ground pins together. First the input ones, if nothing changes connect the output RCA ground pins together, if nothing changes again, from their common run a link to the input RCAs ground pins. All that locally on the RCAs at the back panel plane.
Do all MJE transistors measure about same Vbe? That's voltage between pins 1-3. Also found across each 100R.
For the BC560/550 Vbe is between pins 2-3, easier measurable between Vout and each respective 1R.
For the BC560/550 Vbe is between pins 2-3, easier measurable between Vout and each respective 1R.
13.886-13.746=0.14V difference. Where's the 0.5V difference?
By the way, Vo=Dref-Vbe(BC5xx) in this circuit design. Your figures are compliant.
Indeed, 0.14 V difference.
0.5V was before the led-bars replacement, I'm sorry for the confusion between the measurements.
Took the wrong part from the wrong bag a year ago and instead of checking everything again I just put it there it shouldn't be.