Valleylab Force FX-8C, Service Manual

Page: 97 / 218

Periodic Safety Check
Setup, T
ests, and Adjustments
Force FX-8C Service Manual 5-13
Important
Periodic Safety Check
When testing RF equipment, follow
these test procedures to duplicate
manufacturer test data. Keep test
leads to the minimum length usable;
lead inductance and stray
capacitance can adversely affect
readings. Carefully select suitable
ground points to avoid ground loop
error in measurements.
The accuracy of most RF
instruments is approximately
1–5% of full scale. Using
uncompensated scope probes
causes large errors when measuring
high voltage RF waveforms.
Perform the following safety check every six months to verify that the
generator is functioning properly. Record the test results for reference in
future tests. If the generator fails to meet any of the checks, refer to
Section 6, Troubleshooting.
Here is a summary of safety checks:
• Inspect the generator and accessories
• Inspect the internal components
• Test the generator
• Verify REM function
• Confirm outputs
• Check leakage current and ground resistance.
Recommended Test Equipment
• Digital voltmeter—Fluke 77 or 87, or equivalent
• True RMS voltmeter—Fluke 8920, or equivalent
• Oscilloscope—Tektronix 2445, or equivalent
• Leakage current tester—Use UL load device or commercially available
leakage tester
• Leakage table—per IEC 601-2-2, Figure 104
• 100, 200, 300, 500 ohm, all 250 watt, 1% tolerance, noninductive (Dale
NH-250 or equivalent).
Warning
Electric Shock Hazard When taking measurements or troubleshooting the
generator, take appropriate precautions, such as using isolated tools and
equipment, using the “one hand rule,” etc.
Electric Shock Hazard Do not touch any exposed wiring or conductive surfaces
while the generator is disassembled and energized. Never wear a grounding
strap when working on an energized generator.
Caution
The generator contains electrostatic-sensitive components. When repairing the
generator, work at a static-control workstation. Wear a grounding strap when
handling electrostatic-sensitive components, except when working on an
energized generator. Handle circuit boards by their nonconductive edges. Use an
antistatic container for transport of electrostatic-sensitive components and circuit
boards.