Ametek ZF2 SCR Series, Instruction, Operation And Maintenance Manual

Page: 29 / 52

ZF2/ZF3 SCR Power Controller Troubleshooting
Rev 3 Ametek HDR Power Systems 23
CHAPTER 7 – Troubleshooting
7.1 Customer-Service Program
Although service is seldom necessary, because of the inherent long-term reliability of solid-state
components and conservative design, Ametek HDR Power Systems emphasizes customer satisfaction
by maintaining a rapid-response and cooperative customer-service. If operational difficulties occur,
Ametek HDR Power Systems will provide replacement parts or units quickly, courteously and
efficiently. If servicing problems arise that are not within the scope of the following troubleshooting
guide, service is readily available, as detailed in Chapter 7.
7.2 Troubleshooting Typical Symptoms
The ZF2/ZF3 is considered to be operating properly when its output voltage can be satisfactorily varied
from 0% to 97% of the available input voltage by a control signal. Improper operation of the unit is
usually indicated by one of the following symptoms:
a. No output.
b. Full output at all times, with no change resulting from a control signal change.
c. Output variable from some intermediate value to maximum, but cannot be brought to zero.
d. Output variable from zero to some intermediate value, but cannot be brought to maximum.
The symptoms listed may be caused by one or more of the following: an environmental problem,
faulty input-power or load connections, and the ZF2/ZF3 itself. These possible causes should be
investigated as described in Chapters 7.4 through 7.6.
7.3 Static Precautions when Servicing
Servicing should be performed by qualified personnel only, following procedures described herein.
If troubleshooting indicates a need to replace a component on a printed circuit board or possibly the
entire board, measures to prevent electrostatic discharge (ESD) damage must be taken.
a. ALWAYS wear a wrist strap connected to ground through a 1-megohm resistor when working on
printed circuit boards.
b. Use soldering iron with a grounded tip.
c. Use a non-static solder sucker (metallic) or solder removal braid.
d. Transport static sensitive components in static shielding bags or rails. A new printed circuit board
should be treated as a static sensitive device. A part completely installed on a board does not
make the part static-safe.
WARNING - ELECTRIC SHOCK CAN KILL
HAZARDOUS VOLTAGES exist at the exposed heat sinks and at the load
unless the line-source fused disconnect or circuit breaker is open or off.
This is true even when the SCRs are turned off. Always remove power and
properly lock out power to the unit before attempting any service.
ATTENTION
Printed circuit boards contain sensitive components that can be damaged
by electrostatic discharge (ESD). Observe precautions for handling
electrostatic sensitive devices.