05TV177
KDE-P37XS1, KDE-P42XS1, KE-P37XS1, KE-P42XS1 BC
Subject IRIS
Noisy Power Supply 1144
SYMPTOM
A high-frequency squealing noise (c. 10 kHz) may be heard from T103 on the APS202 Board. This can be checked
by disconnecting the fan. If a high-frequency squealing noise of approx. 10 kHz can be located coming from the
centre of the APS202 Board, T103 is to be suspected. This noise is very distinct from the low-frequency buzz noise
generated by the Plasma panel driver boards X-SUS and Y-SUS located at either side of the APS202 Board.
CAUSE
The small gap in T103 allows both ferrite bars to move and consequently to generate noise.
SOLUTION
Replace T103 as indicated below. The gap of this improved transformer has been filled up with additional epoxy to
prevent the ferrite bars from moving. A black dot mark has been added to distinguish the improved part.
