First quick try:
(I'm french, therefore I do not take any responsability in case you burn your amplifier
):
Standby current
• Preparation of the unit:
Set up the unit in normal position and protect it against the direct air from air conditioning or fan.
Adjustment should be done at temperature between 15° C and 30 C°.
• Control settings:
POWER SWITCH: off
Volume control: Full counterclockwise (i.e. at minimum volume).
(VR801) and variable resistance (VR501, 502, 503 and 504)
Loudspeaker contacts: no speaker connected !
• Setting
A) Remove the housing cover. Then connect the voltmeter (DC) to the power supply unit (IU 2369-1 or 1 U 2422-1).
remark here: "power supply unit" is the correct translation for the term "Netzteibaugruppe" but is certainly not what is meant here -> please check !!!
B) Insert the power plug and switch the unit on .
After ten seconds, clockwise rotate VR5O1 (left) and VR502 (right) to obtain the following voltage 5 ± O, 5 mV DC on your voltmeter.
C) Let it warm up for two minutes and re-adjust VR501 and VRS02 to retrieve 5 ± O, 5 mV DC.
D) If recessary re-do a last adjustment after further 10 minutes.
E) Inject a 1 kHz OmVrms signal into the inputs of the two channels and set the main volume control
to its maximal position.
F) Check that the display of your voltmeter is set to a range of about 10mV or lower and
adjust VR500 (left), VR504 (right) clockwise to obtain 30 ± 3.0 mV DC.
G) After two minutes warm up redo the adjustment of VR503 and VR504 (to get 30 ± 3.0 mV DC)
H) Wait again another 10 minutes and re-check the 30 ± 3.0 mV DC, otherwise adjust again VR503, VR504.