ZETRON 30 Worldpatch, Instruction Manual

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6-1
6. REPAIR
IN CASE OF DIFFICULTY
In case of difficulty, call the Zetron Model 30 Applications Engineering
Department at (425) 820-6363. Engineers are available. Please have the serial
number of the unit and/or the Zetron Order number. If the call is made from the
installation site by the installer or radio technician, the problem can usually be
solved over the phone.
If a problem develops after a unit has been in service for some time, call the
Zetron Model 30 Service Department at (425) 820-6363. If the call is made from
the installation site by a radio technician, the problem can usually be solved over
the phone.
The parts lists for the Model 30 and Voice Delay boards are included in this
section to aid installation or repair of the unit.
TROUBLESHOOTING
COR and Squelch Problems
For the internal squelch circuit to operate properly the receiver audio must be
unsquelched and contain a high percentage of high frequency noise when no
carrier is present. For example, if the audio level for full deviation tone at 1 kHz
is 0.2 Vp-p, then the unsquelched noise level with no carrier present should be at
least 1.0 Vp-p.
1. Key and unkey the PTT on a radio and watch the Carrier LED on the Model
30. The Carrier LED should light solidly when the radio is keyed and go out
when it is unkeyed.
2. If the radio does not provide adequate discriminator level to operate the
internal COR circuit in the Model 30, set JP7 for EXT and connect a wire
from the COR line in the receiver to pin 8 on the Model 30 (see Section 5,
“Tests and Adjustments/Initial Turn-on”, step 5). JP8 sets the COR polarity.
Unreliable Dialing or Misdialed Numbers
1. Check the DTMF deviation on the radio. It should be between 3 and
3.5 kHz deviation.
2. Check the receive level coming into the Model 30 at U1 pin 14 (see Section
5, “Tests and Adjustments/Initial Turn-on”, step 1).