Specifications

Chapter 2: Getting Started
2 – 15
sity spot will be generated in the center of the screen and
will remain there, unmoving, until all HV power is dissi
-
pated from the CRT, which can lead to phosphor burn.
Here is a quote directly from the G05-801 Service Manual
describing this condition:
“On power down, the transistor Q502 shorting the Z signal, draws its operating
power from a decaying +25v line and consequently after a short time loses its abil-
ity to short out the Z signal. If the Z signal is still present, it will turn on Q504 and
greatly decrease the discharge time constant of C506, which maintains the cathode
to G1 bias voltage. If this voltage falls below a critical value, the CRT will turn on
and if the heater is still warm enough and EHT is present on the CRT, an unde
-
flected spot containing very high energy per unit area of display will burn the phos-
phor.[!]
“It is imperative that the Z signal be removed before Q503 loses its ability to short
out this signal. If the signal plug is disconnected, before the monitor is powered
down, this condition will be automatically met. In a fully integrated system where
the generator and monitor are switched off at the same time, the power supply of the
generator must decay before the power supply of the monitor.”
WARNING! SO HEAD THIS WARNING: WHETHER YOUR RUNNING YOUR MONITOR FROM AN
ORIGINAL ASTEROIDS GAME BOARD, OR THE ZVG, POWERING DOWN YOUR G05
MONITOR BEFORE STOPPING VECTOR GENERATION CAN BURN A HOLE IN YOUR
PHOSPHOR!