User Manual

Technalogix Ltd. TM-100 Modulator
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6.0 PROBLEM TROUBLESHOOTING GUIDE
The guide below covers some typical symptoms, possible associated causes and
suggested actions to follow before returning the unit for repair. It is not meant to be all-
inclusive.
Symptom Possible Cause Suggested Action
No output
Weak output
Unit tuned to output channel different from desired
(this occurs particularly on the units which have
green LED on the front panel to indicate “T”
channels and channels above 99)
Input signal is too weak
IF loop cable on rear of unit loose/disconnected
Unit not plugged in or not getting power
Ensure selected output channel is
desired channel
Ensure input signal strength is 1V
peak to peak
Check IF loop cable is securely
attached
Check power cord and power
source, fuse
Excessive noise
Spurious signals
Output level above rated maximum (most often
occurs when changing from high-number channel to
low-number channel, especially to the “T” channels)
IF level too high (most often occurs when routing IF
through scrambler or other external device)
Input signal too strong or no input signal at all
Measure RF output from rear
panel jack and adjust front panel
OUTPUT LEVEL control as
required
Measure normal IF output level
for applied CW/unmodulated
input carrier and ensure same
level is returned to unit after
external processing
Measure video level and pad to
within specified input levels.
Bad/noisy video
Aural carrier interfering with video carrier
Measure Aural Carrier level
and/or adjust AURAL CARRIER
LEVEL control on front panel
Channels do not
change
Delay feature active
Hold channel change switch in
raised/lowered position for at
least three seconds