Some questions about the MTR3000

Note:

Production of the MTR3000 was ended in 2015. It is no longer supported by Motorola Solutions. It is, in my experience, a very reliable repeater if you pay attention to the installation - particularly lightning protection (see this post).

Q. I am working on an MTR 3000 I am connecting an external controller through the 25 pin accessory connector. I have everything working ( I have CPS, the unit is programed, PTT, COR, RX audio, PL-Talkgroup. ) I can not get a TX audio path. I have no transmit audio. Nothing on pin 1 or pin 22.   I have tried J5 the 96 pin connector. I have RX audio, PTT but still no TX audio.  Am I missing something?

A. Some checks:

Is the repeater configured for analogue mode operation? Injecting audio from the auxiliary/system connector is only possible in analogue mode.

If it is in analogue mode, are you able to make the repeater transmit (even though there is no audio)? I know it's obvious but the repeater needs to be transmitting to hear audio over the air.

If you have an oscilloscope handy, check what the voltage is on pin 1 to ground (pins 9; 16; 17 or 18). It should be around 100mV when the controller is producing audio.

If you have a tone generator handy, try injecting a 1kHz tone on pin 1 whilst triggering the GPIO used for PTT. Does the repeaer produce any transmitted audio in this case?

Is the controller (only) producing tones below 300Hz (e.g. PL)? If yes, check whether flat audio is enabled and pre-de-emphasis is disabled in the repeater codeplug. Some controllers have a separate output for signalling and audio so maybe also check this detail in the controller's documentation.

This may be a long shot but I'm not convinced that pin 1 and 22 are electrically the same (i.e. they end up at the same pin on the station controller) so maybe try using either pin by itself rather than bridging them.

If my suggestions don't help, you need to contact technical support. 

Q. We have configured the capacity plus voice linked on the MOTOROLA MTR3000 repeater. After the repeater is turned off and on, the USB port goes offline after 10 seconds. So I can't configure it. The 6 LEDs in the front are constantly flashing. Can you help please?

A. I assume the repeater as working before? If yes, is there anything in your codeplug that could explain this behavior? For example, what is the primary power supply set to?

It might help trying to power the repeater from an external DC power supply as there might be something wwrong with the repeater power supply or something related to that.

If my suggestions don't help, you need to contact technical support.