powersoft D-Cell 504 - Checking the Power Supply; Failure of the Varistor

7 Checking the power supply
Evidence of a fault in the power supply stage is a
blown main fuse (located close to the main switch).
Before replacing it, check if the protection varistor is
also blown. If not, disassemble the power supply board
from the chassis and check all components as illustrated
in the following paragraphs.
If the protection varistor is blown, move on to the
next step regarding the varistor issue
8 Failure of the varistor
A varistor RV1 short circuit, resulting in its
permanent damage, can occur if a mains voltage higher
than 250V
AC
is applied to the D-Cell PSU. In this case
the main fuse is also always blown.
1. Components to be replaced:
f RV1 varistor
f F1 Fuse
We recommend anchoring the varistor with
silicone glue to the nearest capacitor.
FIGURE 8: Fuse.
FIGURE 9: Fuse on PCB.
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