Harman Kardon Hk980 biasing

[Shagma32]

Hi,

With ref to manual and picture. I have to measure +10mV with on lead on speaker (-) and one lead on TP1. With multimeter. However… TP1 has 2pins. Whitch pin do I choose?

I have checked min-max on both pins using my multimeter and rotating potmeter:

TP1 pin1: max +10,5mV min: -18mV
TP1 pin2: max -18mV min:-45,5mV

Measured from speaker (-) and pin…

 

[mbz]

You can measure between either TP1 or TP2 and spkr GND (but disregard the +/- sign) for 10-11mV
or measure between TP1 and TP2 for 20-22mV

Refer to schematic below.

 

[Shagma32]

Hi mbz and thanks. But still I have the same question. TP1 has two terminal points. TP 1:1 and TP 1:2. If I measure from one of these points to speaker ground. I can get these values:
TP1 pin1: max +10,5mV min: -18mV
TP1 pin2: max -18mV min:-45,5mV

I can put potmeter to max, which gives closest value on both ports but still not ideal…

Is it Ok to measure between TP1:1 and TP1:2 for 20-22mV?

When you say TP2, I would assume you are refering to other channel? (Both are label’ed TP1 on my amp..)

Sorry for the following up question. Just wanted to be sure?

 

[Shagma32]

One lead on speaker +, other on TP1:1, then did same measurement on TP1:2. amplifier is now adjusted and ready for use👍