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  #21 (permalink)  
Old 07-24-2014, 5:01 PM
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Yes, it is a low voltage problem not an antenna problem. The engine management system in late model Chevrolet trucks controls the alternator voltage and can bump it up under heavy load conditions. This, obviously, does not happen when the truck is not running. Since the radio works properly when the truck is running it is not a radio problem. So that leaves either a weak battery, which you have had tested, or something in the wiring that is causing a voltage drop. The voltage drop will be greater when the current is higher which lets the radio work in receive.

The green and orange wires to the same point in and of itself is not a problem. Low voltage on the green wire can be a problem.

A quick and dirty test. Take a different known good battery and put it in the truck, or at the very least take the second battery and a set of jumper cables and connect directly to the battery terminals in the truck. If the problem goes away it is the battery. If it doesn't it is in the wiring.
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Old 07-29-2014, 2:20 PM
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Check the bullet connector at the fuses on the power cables. I have seen those cause some strange problems. I always cut them out and splice the wire to the fuse holder when I do an install.
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Old 07-29-2014, 4:29 PM
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It's been a few days. I wonder if he ever got it figured out.
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  #24 (permalink)  
Old 08-01-2014, 4:41 AM
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Jerry I'm thinking you may be on to something with the voltage. I switched all the channels on the cps to run low power to see if that would make a difference. The odd thing is I have a Motorola PM 400 in the truck as well and it doesn't reset like the Astro Spectra does . Could it be maybe the ground?

I was on a scene for 20 minutes helping our local ambulance service doing a lift assist . My truck was left on. The only thing running power wise was my Whelen Liberty Lightbar, my led dash light and my led grille lights . And when I went to holler back to dispatch the radio reset, so I'm wondering if maybe it's the alternator not charging the battery ? It's the Original big alternator that comes with the GM Plow Prep Package. But the truck has a 102,000 miles on it.
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Old 08-01-2014, 5:28 AM
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It could be on either side of the power connections, or even a bad connection inside the radio.

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Old 08-01-2014, 12:11 PM
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Yes the ground is a very real possibility. I usually put an star washer between the ring on the ground lead and the body. It helps cut through the paint and get down to bare metal.
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Old 08-01-2014, 1:59 PM
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You've never responded to the first question in Post #2 about where your radio gets its power from.
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  #28 (permalink)  
Old 08-01-2014, 2:14 PM
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Mike ,

It gets power from the power box off the battery, that comes standard on GM trucks
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Old 08-01-2014, 2:16 PM
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Is there a connection between the power box and the battery and have you checked it for any voltage drop when the radio is transmitting?
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  #30 (permalink)  
Old 08-01-2014, 2:19 PM
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No drop in voltage

I'm gonna try to re do the wiring harness with shrink wrap connectors this weekend rather than crimp connectors.
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  #31 (permalink)  
Old 08-01-2014, 3:33 PM
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Quote:
Originally Posted by DFDDeputyChief8 View Post
Jerry I'm thinking you may be on to something with the voltage. I switched all the channels on the cps to run low power to see if that would make a difference. The odd thing is I have a Motorola PM 400 in the truck as well and it doesn't reset like the Astro Spectra does . Could it be maybe the ground?

I was on a scene for 20 minutes helping our local ambulance service doing a lift assist . My truck was left on. The only thing running power wise was my Whelen Liberty Lightbar, my led dash light and my led grille lights . And when I went to holler back to dispatch the radio reset, so I'm wondering if maybe it's the alternator not charging the battery ? It's the Original big alternator that comes with the GM Plow Prep Package. But the truck has a 102,000 miles on it.

Back on the 24th, I suggested that you measure the voltage and see what you have. If your not doing the simple trouble shooting as others have suggested, then there is not much else the group can do to help you solve the problem.
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  #32 (permalink)  
Old 08-15-2014, 8:51 AM
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Well after a couple weeks of messing around with it I removed the RF filter I had on the Positive line and since then it works fine now . Thanks for the input guys
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  #33 (permalink)  
Old 08-15-2014, 6:02 PM
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OH, you did NOT mention the 'filter'......
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Old 08-15-2014, 6:28 PM
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Doh! Lol
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  #35 (permalink)  
Old 08-15-2014, 7:46 PM
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Yeah my bad . I didn't think that would do anything.... But when my I tried my PM1500 and it wouldn't power up on one cable and it did on another I got thinking ....
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