Ametek DPA1 Series Installation, Operation And Troubleshooting Instructions page 43

Phase/AMP Series DPA1/DCPA1
5-27. Check pulse shaper circuit for power SCR Q1 as follows:
a. Turn off power. Connect the common lead of the oscilloscope to terminal TB2-3. Connect the probe of
the oscilloscope to terminal TB2-4.
b. Turn on power. The oscilloscope should display a pulse train as shown in Figure-4, waveform 8. The
extension or contraction of these pulses is controlled by the BIAS/MAN control. If the oscilloscope displays the
specified pulse train, proceed to paragraph 5-28. If the oscilloscope does not display the specified pulse train,
check the following components; repeat this test if any components are replaced.
(1)
(2)
(3)
(4)
(5)
5-28. Check power SCR's Q1 and Q2 as follows:
a. Turn off power. Connect the common lead of the oscilloscope to terminal X2 on the unit.
probe of the oscilloscope to terminal X-1 on the unit.
b. Turn on power. The oscilloscope should display a waveform as shown in Figure-4, waveform 9. However,
the waveform should by symmetrical for the positive and negative half cycles of the input line Voltage. If the
oscilloscope displays the specified waveform, the unit is operating properly. If the oscilloscope does not
display the specified waveform, check power SCR's Q1 and Q2. Repeat this test if either is replaced.
5-29. Close the feedback loop by resoldering the wire to feedback transformer T2 (which was removed at
paragraph 5-21).
Document 9100030
Silicon control rectifier Q4.
Pulse transformer T3.
Resistors R18 and R20.
Capacitors C10 and C16.
Power Transformer T1.
AMETEK HDR Power Systems
Trouble Shooting
Connect the
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