The service manuel is very helpful, we where able to restore the device to its working operation again.
Text excerpt from page 129 (click to view)
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A
A
Display RST MASK 03 (Green). / [MKS S53]
Is there erroneous discharge (abnormal dead cell)? (Check on the PANEL 1-ADJ menu.) No Set VOL OFFSET to the current setting value minus 48. / [VOF ***]
Yes
Replacement of abnormal circuits or re-replacement of the panel required
B
Determine the current VOL OFFSET setting value as the final value.
[To the Main flowchart (2)]
Recovery flowchart (1-3)...Changing the VOL OFFSET setting voltage
C
[From the Main flowchart (1) ]
RST MASK 02 (Red)
Gradually decrease the VOL OFFSET value until disappear the discharge (dead cell). The VOL OFFSET value must be 117 or greater.
Current VOL OFFSET < 117?
Yes
Replacement of abnormal circuits or re-replacement of the panel required
