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If the answer is 1) Yes
(Green Power LED will be always on)
This indicates your providing Vs and Va voltage to the X-SUS and Y-SUS PWBs. Use an Analog Scope. Look at
the outputs from the X-SUS and X-BUS. Use the Top Pin of the connector going to the Panel, on either side.
See if there is activity.
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Top pin to Panel X-BUS PWB 29V p/p
Top pin to Panel Y-SUS PWB 460V p/p
No Activity will usually indicate a defective PWB.
But if no activity is seen, before condemning the PWB,
pull the Ribbon cable from that PWB to the Panel and check again.
If activity returns, this will usually indicate a defective panel.
Remember: You have to pull all Ribbon Connectors before condemning the
PWB.
If the Panel is defective with this process, in most cases evidence can be seen
on the screen.
Example: If the top ribbon cable is pulled, the Top of the screen will be
black, but the bottom will have raster.
If the answer is 2)
(Green Power LED will go Green the Go Off)
Brief rise then collapse of the Vs and Va voltages.
This indicates a "Load" on the line.
Pull the CN-64 connector feeding Vs/Va voltages to the X-SUS.
Take an ohmage reading from the Va and Vs lines on each PWB.
This means you have to read the Connector on the Power Supply and the pulled connector going to the X-SUS.
See if there is a low value. Low value indicates a defective PWB.
Normal reading should be infinity. (Using the diode mode on the DV/Voltmeter, there will be a brief charge
time, then infinity.) In other words, it may appear as a low ohm reading, but should rise to infinity or open.
(Also not, if there is a charge on the line, the meter may show a low. You must Pull the CN68 connector and take
a reading again).
The line should now be infinity when reading the Power supply pins for Va and Vs and when reading the
connector going to the X-SUS PWB.)
If a Low is see on the connector, pull the CN32 Connector. (Bottom right hand plug on the Y-SUS PWB).
CN32 feeding Vs/Va voltage to the Y-SUS PWB.
Y-SUS PWB.
