Service Position; No High Voltage Testing Position - Sony CPD-G400 Training Manual

Service Position

Warning-When repairing any electronic product DO NOT PLUG THE
PRODUCT DIRECTLY INTO AC. Plug the product into an isolation trans-
former and the transformer into AC to reduce damage and the danger to
you when servicing.

NO High Voltage Testing Position

This position allows you to troubleshoot almost all the stages of this moni-
tor except the HV stages and the sections that are fed voltage from the
flyback secondary. These sections can be tested with an ohmmeter or by
repositioning the chassis for the full voltage testing.
Sections Tested without HV
Full Power Testing
L.V. Power Supply Vertical Dynamic Focus
Video Processing G2 Control section
Vertical Output
Horizontal Output,
Pincushion
Horiz Dynamic
Focus
Convergence
CPU & DPU
Partial Testing No Power Testing
High Voltage stage
General Procedure:
1. Remove shielding to expose the area you need to test.
2. Leave the Degaussing coil, convergence yoke, rotation coil, and HV
anode lead unplugged.
3. Reconnect the main yoke to prevent the protection circuit from acti-
vating.
4. Disable the HV from the top or bottom of the board by shorting the HV
Output transistor's Gate to Source leads.
5. Plug the monitor into AC.
6. Move the control button to the left and hold it there for two seconds
while the monitor enters the Aging Mode. This will prevent the moni-
tor from entering the (Active Off) Power Save Mode without video
input. The Active Off Mode shuts down the power supply.
Main
Yoke
Connector
No HV Testing Position
viii
Kill HV
Short Gate
To Source