Repair; In Case Of Difficulty; Service Notes - ZETRON 37-MAX Installation Manual

IN CASE OF DIFFICULTY

In case of difficulty, call Zetron at (206) 820-6363 and ask for Model 37-MAX technical support.
Please have the serial number of the unit and/or the Zetron "Order Number" available when you call.
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, the service technicians should
call Zetron just as they would for a new installation. Zetron's Applications engineers will happy to
help figure out what has changed about the system.
The parts lists for the Model 37-MAX are included in this section to aid in the evaluation,
installation, or repair of the unit.

Service Notes

1. If a programmed value is out of range for the parameter in question, the default value will be
used instead.
2. If the unit gets "locked-up" due a lightning hit or power line spike, a microprocessor reset can be
performed by sending any valid DTMF digit continuously for more than 20 seconds. This
removes the need to drive to the site to reset the unit.
3. If the audio does not sound correct, perform an audio sweep test by generating an audio signal (of
known deviation) on the repeater receive frequency, and monitor the deviation on the repeater
transmit frequency. As the frequency of the test is changed, the transmit deviation should be
fairly flat from 300 Hz to 2500 Hz. If the deviation changes by more than a few hundred hertz,
try moving jumper JP6 in the Model 37-MAX to flatten the response.
4. The Carrier LED must follow carrier activity on the channel. If it is always off, the Model 37-
MAX will not detect CTCSS tones. If it is always on, the Model 37-MAX will usually time out.
The Model 37-MAX is a microprocessor controlled device, which means that the operation can
change depending on the software the microprocessor is running. The processor controls the audio
repeat path, PTT, Status LED, and CTCSS decode.

6. REPAIR

6-1