Epson Stylus COLOR 1160 Service Manual page 67

EPSON Stylus COLOR 860/1160
Table 3-10. Isolating the Faulty Part on the Power Supply Board
Step Check Point
9 Is the main switching Check the electrical continuity of the switching FET
FET (Q1) defective? by trying four patterns below. Be sure to pay
attention to the polarity. If the main switching FET is
good, the findings should be as shown under the
figure.
Step 1: Off, Step 2: On, Step 3: Off, Step 4: Off
10 Is the NPN connection Check the electrical continuity of the NPN
transistor defective? connection transistor on the C298 PSB/SE board
by trying four patterns below. Be sure to pay
attention to the polarity. If the NPN contact
transistor is good, the findings should be as shown
under the figure. Note the NPN connection
transistor is shown in the circuit diagram as
described below.
Step 1: On, Step 2: Off, Step 3: Off, Step 4: On
Troubleshooting
Action
Overview
Table 3-10. Isolating the Faulty Part on the Power Supply Board
Step Check Point
11 Is the PNP connection Check the PNP connection transistor on the C298
transistor defective? PSB/SE board in the same manner described in
the previous step.
Step 1: Off, Step 2: On, Step 3: Off, Step 4: On
12 Is the +5 V regulator Check the IC51 for the oscillation waveform
(IC51) defective? (measured by using a oscillo scope) output from
the Pin 2. If the output waveform is as shown
below, it means the IC51 is working properly.
Revision C
Action
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