Maratrac help - beeps wildly when turned on

[kb0wxk]

This Maratrac came to me in the bottom of a cardboard with other modern Motorola radios. I asked a friend in the radio club to reprogram the radios to local ham repeaters and he said he could program the Maratrac. We agreed on a list of repeaters in the area.

He programmed all of the radios correctly and I have been using the GM300s on projects. So a year or so later I pull out the Martrac and attach a 2M antenna to confirm I can transmit and hear the audio on the my scanner. Everything checks out and I assume all is OK with the radio. I realize some of the repeaters in the list are too far for me to connect with. So I reach out to the friend again to discuss programming the Maratrac again. Well he is not responding to any of my attempts to talk to him.

I decided to just work with what I have as I can reach many of the repeaters that are programmed in the Maratrac including the club repeaters. When I turn on the Maratrac, it starts beeping wildly and you cannot control it. I decided there must be an issue with the advanced control head so I purchase another one. It comes in and I test it. The radio works fine and the wild beeping no longer occurs.

Today, I went to set it up in the shack room. It starts wildly beeping with the new control head.

The wiring is the fat red cable to the positive battery terminal and the fat black cable to battery ground. The radio came with a long 18 gauge wire with a ring terminal which is connected to both the green and orange connectors from the control cable. It came like this and I made no adjustments to the programming of the radio. I did cut off the ring terminals and installed Anderson power pole connectors so the unit would be compatible with my E-Comm setup.

I read in an article that the 18 gauge red wire and the ground wire can be hooked up without the fat red cable and the radio will turn on but will not transmit. So I hook that up and the radios works (without the beeping) with both control heads. Obviously, it will not transmit because the fat red cable is not hooked up.

Here is the video of the unit beeping:

The model# is T73XTA7TA7BK which should translate to 100 Watt, 136- 174 Mhz, 99 channels, Advanced control head, B revision.

Picture below shows how the 18 gauge wire is connected to the control cable. I wondered if I did not have enough amps through the Aston power supply which supplied on 11 amps. I hooked up to battery and the beeping starts as soon as I turn it on.

I am running this fat red and fat black cables through Anderson power pole connectors now. My friend worked with it using ring terminals. Could this be the source of this problem and I need to put back on ring terminals?

Steven
KB0WXK.

 

[n3obl]

When its doing that try hitting the channel up or down. Looks like something is screwy with the channel selection.

 

[kb0wxk]

n3obl - I thought about what you said. I will have to hook it all up again to test your suggestion. If that does not solve it, I will put the ring connectors on to see if that makes a difference.

When its doing that try hitting the channel up or down. Looks like something is screwy with the channel selection.

I was also thinking that it does not beep when the fat red cable and the channels go up and down when hitting the button. Everything is normal until I hookup the fat red cable.

 

[petnrdx]

That is the way they act when the connectors are not making good connection.
You should hook up all three wires to make sure all the circuits are getting powered up properly.
Large red to +, large black to - and the smaller red that is connected to the orange and green should also go to +.
It is REALLY common for the MARATRAC and M400 to act that way if the large plug on the radio is not completely seated.
And no, the ring terminal won't make a difference.
But the green, orange and the large red have got to be at the exact same potential or the radio acts really weird.
And if no one has adjusted the VCO's on the radio, it might not work properly on 2M.
The design of the radio is 136 to 174, but will really only perform well over a 24 Mhz spread within that range.
So if the radio was tuned up for the high end of the design range, like where the USFS freqs are it might need to
be aligned.
Especially if you want to use the 145 range repeaters.
They are great radios once you get them set up right.
I have one with the HHCH that I use.

 

[Kitn1mcc]

could be some crud in the control head

 

[kb0wxk]

I replaced the control head. Both control heads exhibit the same behavior.

 

[kb0wxk]

Thanks everyone who replied on this. pethrdx said something in his reply that made me think. I was hooking the fat red to positive and the fat black to negative on the battery. Then to turn on the radio, I would touch the 18 gauge (ignition sense) wire to the positive terminal of the battery. This would start the wild beeping.

perthrdx said:
But the green, orange and the large red have got to be at the exact same potential or the radio acts really weird.

So I shut the radio off and attached both the fat red wire and the 18 gauge (ignition sense) wire to the battery terminal with clamping bolt. It did not come on until I moved the on/off switch on the bottom of the control head to on position. There is no more beeping. Others may encounter this and I wanted this explanation to be posted on the forums.

I will continue to work with radio and start programming next. Thanks everyone who read this and responded with suggestions.

Steven
KB0WXK

 

[kb0wxk]

I moved the Martrac to the shack room and hooked everything up as I described. Unit powered up without beeping. Then it would not transmit. It was hooked up to a Astron desktop power supply with a max output of 11 amps.

I thought the only difference is I had a car battery when I was bench testing. I think I read the Maratrac specs are 22 amps required to transmit.

I moved the battery to the shack and hooked it up. It started transmitting and I am making the local club repeater. I am ready for the net tonight at 7:30 PM CST.

I guess I don't know how the radio is able to determine it can or cannot transmit based on amps available from the power source. Anyone care to explain?

 

[Kitn1mcc]

They radio could have had the power turned down. also that astron will offer 15amps peak. i used to run a fleet a maratracs back in the 90s they run about 15 or so on tx

 

[n3obl]

You will need more than 11 amps. I would recommend a 20-25 for that beast.

 

[davidgcet]

the radio does not know how many amps are available. it will try to draw what it needs to generate the tx power it is set to output. your power supply is not capable of that so it shuts back. then the radio cannot draw enough to power everything and therefore cannot tx. and yeah a vhf is gonna draw around 20A to do 100 w, plus or minus a few. and if someone has been peaking on it that could go way up, i have seen them put out 150+ before, but they will not do it much or for long. it should be tuned to put out 90-100 watts on 13.8 input voltage. and no, 10 watts or so less will not be noticeable.

 

[k9wkj]

just to pour some more soup in the pot (and it doesn't have anything to do with the OPs issue)
the VHF Maratracs (low band splits and high band) have terrible power and deviation control issues when run out of their normal ranges
it is a firmware limitation, they pull data from a lookup table, which contains the power and deviation levels it should be using for the programmed frequency
if I "recall" it has 12 choices to pick from, and if it cant find a solution it will just randomly pick values
which is why they seem to put out 150W for no good reason
one can use a updated firmware image that contains the proper values for use in the ham bands
this does require a complete alignment after burning the new image to the EPROM
so the process is not for the fearful
I have done 6M and 2M radios with good results
but the investment in time and equipment along with learning how to UV erase and burn the EPROMs is considerable
the fix of adding a accessory pot to the power control circuit works, but only for that frequency you set it for