Multimeter Tests
148
MAX-635G
Stressed Balance
Stressed Balance
Stressed Balance
is an optional test that continuously generates high
voltage (135 VDC) to the cable pair under test while measuring balance.
The high voltage
stresses
the conductors in order to reveal imbalances that
may otherwise be hidden with the normal
VF/AC Balance
test.
The test is very similar to the classic
stress
test well known in North
America. Compared to the VF (longitudinal) Balance test, values for the
Stressed Balance
test are depicted as follows (but check your own
methods and procedures):
good
20 dBRNc
marginal = 20 to 30 dBRNc
bad > 30 dBRNc
In general, a pair that
stresses
25 dBRNc is well balanced for POTS and
ADSL internet service. However, higher speed ADSL2+ and VDSL2 circuits
should stress
20. A low stress value (> 20) indicates imbalance on the
pair, which can have different causes. Most common causes are grounds
and shorts, but also one-sided series resistance (sometimes also called
high-open, high-resistive fault, or
dirty open
). Poor or failing splice
connectors/beanies also case minor imbalances affecting higher speed
DSL circuits.
Watch the stress level, and if you see an increase or jump after a minute or
two or more, the
stress
has worked through some corrosion and thus
revealed an imbalance. However, if the stress improves and you see a
lower value after a minute or two, then the stress voltage may have dried
up some moisture, thus hiding a wet/damp fault which will appear again
when more moisture works its way back into the fault.
When you have a poor stress value (> 25), the next best step is to isolate
the imbalance by running the
Pair Detective
test.
Summary of Contents for MAX-635G
Page 1: ...User Guide Copper and G fast VDSL2 ADSL2 Multi play Test Set MAX 635G www EXFO com ...
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Page 270: ...TDR 260 MAX 635G Continuous Examples of Common Faults Short Fault ...
Page 271: ...TDR Copper and G fast VDSL2 ADSL2 Multi play Test Set 261 Continuous Open ...
Page 272: ...TDR 262 MAX 635G Continuous Bridged Tap ...
Page 273: ...TDR Copper and G fast VDSL2 ADSL2 Multi play Test Set 263 Continuous Splice Joint ...
Page 274: ...TDR 264 MAX 635G Continuous Peak Function ...
Page 275: ...TDR Copper and G fast VDSL2 ADSL2 Multi play Test Set 265 Continuous Dual Trace View ...
Page 276: ...TDR 266 MAX 635G Continuous Load Coil ...
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