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•The (3) versions of the Switching IC are shown; G, F and X. These pin
out schematics of the ICs can be used to assist with troubleshooting.
•Check the ICs VCC for approximately 14V. This is the StartUp and
RunDC voltage that is required to power the amp.
•Check for the Ramping Voltage at the Feedback Pin. This voltage will
vary between models, but .7VDC is the average measurement. Some
PWBs have shown 1.4VDC at this pin.
•Check for DC voltage at FET input. It should be the same as the Input to
the Transformer and is usually about 170VDC.
•Check that the FET is not shorted to GND. Ensure the Power Supply is
Off before making this measurement
Always Replace the IC and the Capacitor on the VCC input together.
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