High Voltage Power Supply Replacement - EDL Displays 6120 Operation And Maintenance Manual

HIGH VOLTAGE POWER SUPPLY REPLACEMENT

P/N 6119-0107-03
Tools Required: 1. Screwdriver, straight slot
2. Screwdriver, Phillips #2
3. Nut driver, 1/4"
4. Insulated lead wire 12-15 inches long
(No. 18-20) with alligator clips on both ends.
Replacing the High Voltage Power Supply involves contact with dangerous high voltage
elements. Follow instructions carefully and observe all safety precautions!
All efforts should be made to isolate the fault to the High Voltage Power Supply (HVPS) before
beginning replacement.
Before replacing the HVPS consider the following:
1. All BNC signal input connections on the rear panel have been checked for proper
connection and the signal source is operating properly.
2. Front panel controls have not been inadvertently set to produce a no raster
condition.
3. HV disable and sync lights have been properly interpreted.
4. Low Voltage Power Supply (LVPS) has been replaced (the LVPS develops the
input voltage for the HVPS).
5. When the monitor is turned on there is normally a high voltage "crackle" sound as
the high voltage builds up to 25 KV. If there is an audible "crackle" at turn on, the
25 KV is present.
6. If the monitor is functioning but out of focus, the HVPS focus control may need a
simple adjustment. Refer to the High Voltage Power Supply Alignment Procedure.
7. The CRT filaments are visibly lighted through the top rear of the cabinet.
REPLACEMENT PROCEDURE
1. Turn a.c. power OFF at the front panel.
2. Disconnect the monitor a.c. power cord and all coaxial cables on the rear
3. Wait twenty minutes for voltages to discharge.
4. Remove the enclosure by removing four screws and sliding the enclosure to the
rear. (Model 6119 only)
4a. Remove the #6-32 x 3/8 FH screws and remove top cover. (Model 6115 & 6116
only)
CAUTION! High lethal voltages could be present at the CRT anode - follow
6115 - 6120 Operation and Maintenance Manual ©EDL Displays, Inc. January 1997
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panel.