Specifications

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SECTION 5 MACHINE TESTING / TROUBLESHOOTING / SERVICE
5.5.1 Coupling Circuit
The coupling circuit consists of resistor R9 (39kΩ, 2W) and capacitor C4 (20μF, 400Vdc). The purpose of
this network is to prevent DC power from owing into the primary of the main transformer (T1). C4 acts
as a short to the 20 KHz AC power and acts as an open circuit to DC.
Testing:
It is recommended that a capacitance check be done on C4; however, with a meter in the diode scale the
value read should increase showing that the cap is charging up. This is a good indication that this is a
good capacitor.
For R9, perform a resistance test. The meter should read approximately 39kΩ.
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