Onkyo tx-nr414 shutting off after few seconds

[Roberts]

Hello again.
I am struggling for long time now with finding fault on Onkyo tx-nr414.
Unit shuts off after few seconds when turned on.

Diagnostics mode works except for: It can not engage OPERATION CHECK 8 - Auto Measurement mode as it instantly shuts off.

Voltage to ground from two bias channel points is high in my opinion (150 and 220mv).
Checked preamplifier board and all seems ok to me, especially 220mv channel.

Firmware is good

Any suggestions?

[Roberts]

Let me correct myself.
Diagnostics mode works except for: It can not engage "OPERATION CHECK 7" - (3-0~3-14) as it instantly shuts off.