sorry @MrChips, I didn't add the minus sign where the multimeter displays it

 

There is no need to indicate the sign for 0V.

I think that you are identifying the transistor pins incorrectly.

Show three photos of the readings on the DMM with the connections to B, C, E, of Q559.

 

Myślę, że wszystko w porządku, schemat, który pokazałeś, przedstawia spód płytki
If I understand something wrong, please let me know

 

I see the confusion.
The actual board does not match what is shown in the Service Manual. I will try to find the correct documentation.
Is there a board revision number printed on the board?

Edit:
Sorry, I think we are looking at the board from the reverse side.
Give me some time to analyze this situation.

 

This is board layout looking from the component side.

Q559 and Q560 are PNP, 2SA1302

 

This is what I can tell from your photos:

Q559 2SA1302

B +51.75 V
C -51.80 V
E +51.82

Now go back and repeat for all four transistors, Q557, Q559, Q560, Q558, going from left to right, B C E.

 

Teraz wróć i powtórz te same czynności dla wszystkich czterech tranzystorów Q557, Q559, Q560, Q558, idąc od lewej do prawej, BC E.
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Pomiar E Q560 daje zmienne dane

 

Ok. Thanks for the readings.

Unsolder and remove Q557 and Q559.
Repeat the measurements.

 

Ok. Thanks for the readings.

Unsolder and remove Q557 and Q559.
Repeat the measurements.

I desoldered Q557 and Q559. New measurements

 

There are problems with both channels. We have to look at DC voltages before the power amp stage.

The LEFT channel schematic is shown. The RIGHT channel is a copy of the LEFT channel.
Locate TP401 (LEFT channel) and TP402 (RIGHT channel). Measure the voltage at pins 1, 2, and 3 on both TP401 and TP402. The expected voltages should be low, less than 1 V or close to 0 V.







TP401 and TP402 are shown. You will have to reverse the image.

 

Locate TP401 (LEFT channel) and TP402 (RIGHT channel). Measure the voltage at pins 1, 2, and 3 on both TP401 and TP402. The expected voltages should be low, less than 1 V or close to 0 V.

The voltage on TP401 and TP402 is approximately -15 V across all pins. After a few seconds, it increases to -57 V across all pins. The measurement was taken with one probe connected to ground and the other to the pins.

the measurement according to the instructions is below 1v

 

There should be a couple of voltage regulators somewhere on the board (7815 and 7915). Check for poor solder connections on these regulators. This is a common failure point.

 

@MrChips
I'm afraid the measurements so far are incorrect. I connected one multimeter probe to the speaker's negative output, thinking it was grounded.
Connecting the probe directly to the amplifier chassis gives different results.
I apologize for misleading you.
All the points I measured earlier are now around 0V.

 

That's fine. We need to measure the supply voltages on IC501 and IC502.

Here are four points to measure:

#1 IC501 pin-8 at lower leg of R515 (it could be a jumper)
#2 IC501 pin-4 at C515 or Q503 emitter
#3 IC502 pin-8
#4 IC502 pin-4 at C516 or Q504 emitter

You could measure the voltages directly on the IC pins if you are careful not to create any shorts when probing around a live circuit.

 

That's fine. We need to measure the supply voltages on IC501 and IC502.
[/CYTAT]

at all points 0v

 

Are you comfortable reading the circuit schematics and matching it with the PCB layout (reversed image)?

We need get the voltage readings of B, C, E of Q501, Q502, Q503, Q504.

If you cannot safely make contact to the transistor leads, look at the shematics and PCB layout. You will be able to find other components that share the same load.

Again, don't make things worse by causing any accidental shorts.

 

Are you comfortable reading the circuit schematics and matching it with the PCB layout (reversed image)?

I think I can do it

We need get the voltage readings of B, C, E of Q501, Q502, Q503, Q504.

Q502, Q504 are desoldered. Does it matter?
@MrChips maybe a stupid question, should each transistor leg be measured to ground?

 

All voltage measurements are made with respect to GND unless specified differently.
If the transistors have been removed, measure at the pads with respect to GND.
If the transistors are installed, make the measurement any more convenient component connected at the same node.

LEFT and RIGHT channels are shown below for convenience.