I tried the following on my vt60, and I'm 55 hours in!!!
Do not deviate from the instructions, as you could do something in intended.

Press and hold the {VOL -} button ON THE PLASMA TV.
Then press the {INFO} button on the remote control 3 times.

"Start Adjustment Menu" message will be displayed followed
by the Service Menu after few seconds.

ADJUST {Picture Adjustment}
WB-ADJUST {White Balance Adjustment}
OPTION {Option Setting}
V-SUS {V-SUS Adjustment}
AGING
SRV-TOOL {Service Tool}
{1} & {2} buttons move through options

Press the {2} button once to select "SRV-TOOL".

Then press the {OK} button to access it.

Using the cursor keys, highlight the right side
of the last item "PTCT :00.00.00.00.00" :





Then press and hold the {MUTE} button for 3 seconds.

Time and Count will be displayed in red color:



__TIME = Hours : Minutes of operation.
COUNT = Times the Plasma was powered on.

To exit, unplug the power cable.