Debugging The Monitor - Vector G08 Series Faq

G08 Vector Monitor Guide

DEBUGGING THE MONITOR

Ok, to debug the monitor, you will need a known working game boardset and power supply. Hook
up the power and video inputs to the monitor.
Now, unplug the connector that goes to the monitor yoke. This removes the load off of the
deflection board so nothing will burn up if some there is a problem, and allows you to take direct
reading of the inputs to the yoke. You need either a scope or a digital auto-ranging multimeter
because the voltage at the yoke inputs is going to be swinging from +62V to –62V very quickly.
On an auto-ranging multimeter, you will see a bunch of random numbers between +62V and –62V.
This will indicate the deflection circuit is working. During this time, there will be no deflection of
the beam, so the beam will shoot straight to the center of t h e monitor. Do not test like this for a
long period of time because it may damage the phosphors. However, this is normally not a
problem because it should take less than 30 seconds to determine the output of the deflection
circuit.
Since getting to the pins of the yoke input are difficult to get to, you will want to make a connector
with wires similar to that of the yoke itself. Plug in your "fake yoke" connector and attach meter
probes to it instead. Pins 1 and 2 are the Y output, and Pins 3 and 4 are the X output.
Ok, we are ready to begin. Connect black and red multimeter probes to pins 2 and 1 respectively
and power on the game. Note the values for a few seconds. Power the game off. Connect the
black and red probes to pins 3 and 4 respectively and power on the game. Notes the values for a
few seconds. Power the game off. Random changing values, either negative or positive, are good;
static numbers near 0, +62V or –62V are bad and there is something wrong with the deflection
circuit or the custom chip.
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