Motorola Syntor X9000 working without ground

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k9.hazmat
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Joined: Fri Apr 08, 2005 10:43 am

Motorola Syntor X9000 working without ground

Post by k9.hazmat »

I knew I had a bad ground on my radio. Everytime I opened the trunk it would flicker and I wouyld lose my scanlist. I knew it was the ground because it was a temporary fix until I got a good connector. I haven't had a problem with it in a few days, but I was still going to fix it today. So I opened the trunk to see if it flickered. Nothing. Cool. I went to disconnect the wire and it wasn't there. It was laying on the carpet in my trunk. I thought it could possibly be grounded out, so I held it in the air away from anything, and the radio was still working just fine. Are these radios this flaky that stuff like this is normal? I had a rough time getting a good enough ground when I first installed it. Now it doesn't even need a ground.. Any explanations?
Thanks
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kb0nly
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Post by kb0nly »

Most likely the radio is still operating because it is getting a ground through the mounting plate. I assume you have the mounting plate fastened down in the trunk?

The main Black lead, the main ground, can be disconnected and the radio will still run. I know this from experience when i was trying to figure out why one wouldn't transmit full power. The main Black and Red leads supply power to the drawer and to the final PA, chances are if you tried to transmit without that ground connected you would find that your not getting much power out.
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nmfire10
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Post by nmfire10 »

Not sure if it will work with that model, but often it can find a ground through the coax shield, or hell, even the mic hangup. This can be rather destructive if you try and draw 20 amps through a microphone hangup lead....
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kb0nly
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Post by kb0nly »

Yep, the coax shield, forgot to mention that one. That's another source of ground when the main ground lead gets disconnected. I have seen bad things happen myself when not properly grounded.
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k9.hazmat
Posts: 14
Joined: Fri Apr 08, 2005 10:43 am

Post by k9.hazmat »

No, it's not permanently mounted. Must have gotten the ground through the coax. Either way, I fixed the ground, so shouldn't be a problem now.
Thanks..
tvsjr
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Post by tvsjr »

This is why watching your grounds is *extremely* important. Most likely, ground was obtained through the coax shield. WHen the trunk was opened, it's path to ground became marginal (they're pretty marginal to start with... you should add a copper braid to the trunk lid from ground to ensure a good ground plane for your antenna) causing the radio to drop.

This is also why you don't want to take the ground side of the radio directly to the battery... if you lose the automotive runs from the battery - to the frame, when you try to crank, ground will be pulled through your radio and out whatever path it can to ground. Needless to say, you'll get an impressive light show.
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