HP-3468A, Display Voltage VDC

[Uli]

Hi technicians,

because of the HP-IL connection (and because it is a wonderful device) I have bought a HP-3468A in very good condition.
It works with 230VAC, 50Hz. Selftest is okay. But... after switch it on, without measuring, in VDC mode, display shows +2,86...VDC. In VAC mode it shows 0,001 VAC. If I check the voltage of a new AA battery it shows 1,62 VDC. AC voltage from the net is shown with 231 VAC.

So, measuring seems to be ok. But I am amazed about the +2,86 ... VDC without any measuring device.
Is that normal? Do you have any idea?

Uli