9
To seat each vacuum tube properly,
ensure that the PL–L is powered off.
Disconnect the ACPS AC power supply
unit and by using the screwdriver from the
toolkit, remove the top plate. If the unit has
just been powered off, please wait 5
minutes for the vacuum tubes to cool
down before handling them. Wearing the
glove, place two fingers around the
cylindrical part of a vacuum tube to hold it
firmly. Push the vacuum tube very gently
in a downward, vertical motion until it is
completely seated.
In the unlikely event that vacuum tubes
became unseated in transit, please refer
to the following diagram to identify the
vacuum tube required at each socket
position and place them in the manner
described above.
The PL–L is also furnished with 1 vacuum
tube usage timer. It is mounted internally
on the printed circuit board as shown on
page 12. When the power is turned on,
this usage timer will time the usage of the
vacuum tubes up to the maximum limit of
5,000 power–on hours (1division
corresponds to 500 hours).
When the timer indicate close to the 5,000
hours maximum, vacuum tube
replacement is recommended. We
suggest that you use
the spare tube kit
available from your authorized dealer,
which includes Nagra–tested vacuum
tubes as well as one new usage timer.