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How to diagnose Samsung plasma failure using test patterns

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tom667 picture

MODEL: Most Samsung plasmas

ISSUE: Cannot identify whether failure exists in main board, control board,
sustains or PSU.

DIAGNOSIS: Locate test header on control - should be 4x2 or 6x2.
Jumper appropriate pins (refer to service manual or PCB)

If you get test patterns:
- sustains, PSU, control okay
- main bad (control POSSIBLY bad - if input receiver bad)

If not:
- sustains, PSU, control or main are bad

Then identify failure in PSU - test output voltages
- if bad, fault lies in PSU, shorted sustain or main not turning
the PSU on

Then identify sustain board failures:
- unplug X-main, check if powers up and Y-main functions
(dim picture)
- unplug Y-main, check if powers up
(no picture)

Then identify control board failures:
- test SMD fuses
- scope LVDS waveforms going to control (if possible)

Might be main board failure. To confirm, test main board:
- blindly select audio source using INPUT button