Heat from the main heatsink slowly dries out this capacitor (C104 on the schematic). Unlike typical failures that cause ripple or shutdown, C104’s degradation silences the , causing the controller to sit in an infinite reset loop. The LED still lights because it draws from the input side. A $0.60 capacitor renders an $1,800 module dead.
The string itself offers the first clues. In engineering shorthand, “ETG” typically points to one of three families: etg-63a
Given the suffix “-63a”—where “63” often denotes a revision of a 1960s-era military specification (MIL-STD-63) and the lowercase “a” indicates a minor variant—the most plausible classification is a for legacy systems. Heat from the main heatsink slowly dries out