Cencom red quits then turns back on

[Dave]

I have a wierd problem. I have a Whelen Cencom Red light/Srien controller, And im having an issue when i use my CDM-1250 radio the siren controller makes a click like a solenoid noise and all the exterior lights go out. Now when this happens the radio is still on as well as the control head still shows the T/A on and whatever level of lighting im on. This only will happen if im outside the truck trying to use the mic. Keep in mind that im not over streching the mic cord. and if i leave the PTT pressed after around 5 sec everything comes back then happens again. I have checked both power and ground with my power probe. im just lost on what it could be. Everything points to a bad mic but i dont see how it would affect the lights. Any ideas????


Thanks in advance


Dave

 

[SireLite]

Make sure all your connections are not loose.

 

[Dave]

Make sure all your connections are not loose.

I have checked them and none are loose. they all seem secure.

 

[Luismariadarlene]

maybe bad wiring low amperage or something

 

[Dave]

maybe bad wiring low amperage or something

I just bought this vehicle in august and installed all of this equipment then. All has been well untill the other day. i have checked all power and grounds all plugs are tight and the only thing that makes this happen is when you key up the mic while moving the cord ie: using mic while standing just outside of my drivers door. im really stumped, I havent changed the mic yet with a known good that might be my next step.

 

[EVModules]

That's interesting, my first thought is RF issue from the radio but you say that this only occurs when you pull on the mic... Try clamping down the mic cord next to the radio to relieve strain on the jack. It's almost always done with my upfits.

 

[Dave]

That's interesting, my first thought is RF issue from the radio but you say that this only occurs when you pull on the mic... Try clamping down the mic cord next to the radio to relieve strain on the jack. It's almost always done with my upfits.

I went out on lunch and was messing with it and i have isolated it to the middle of the mic cord. Almost like it was pinched at one timebut the cord looks just fine. and the cable is secure next to the plug. So my thought is that the mic is bad.

 

[Dave]

UPDATE:


I have replaced the mic. made no difference and have had this lowband radio installed in 2 other vehicles since this problem and both vehicles ac the same.. but now it doesn't matter if you wiggle the mic cord. now I do have a cdm1250 in vhf high that doesn't do this and I have even swapped mics and no change. maybe the cdm is bad????

 

[Outsider]

Check your antenna connection at the radio to make sure it is tight. How close is the actual antenna from the CenCom? If you have access to a different antenna with a magnetic base, plug that in and try temporarily relocating the antenna. This will help solve your issue.

 

[tvsjr]

Correlation does not necessarily imply causation. I.e. your mic cable stretching may have nothing to do with the problem.


Likely suspects are voltage drop when you key the radio (especially if you're sharing your power wiring between the radio and the Cencom) or RF getting in. You can check the former with a voltmeter... the latter, you would start with an SWR meter or antenna analyzer and go from there.

 

[Dave]

Check your antenna connection at the radio to make sure it is tight. How close is the actual antenna from the CenCom? If you have access to a different antenna with a magnetic base, plug that in and try temporarily relocating the antenna. This will help solve your issue.

I have bought new antenna eveytime I swap a vehicle and the problem has followed. the antenna is on the front fender and the radio is behind the seats on my crew cab truck. and I have tried a mag base with no change.

 

[Dave]

I have 4ga power and ground going back to a fused buss bar its just weird that my high band doesn't do it just the lowband. I have swapped the power plug antenna

 

[Zoe]

Took delivery of a cruiser in my town a few years ago that had similar problems with the CenCom... every time the radio was keyed the warning lights would turn off, then immediately turn back on after the radio stopped transmitting.


The problem ended up being that the antenna coax was run along side the power/control wires for the CenCom (all down the driver's side of the vehicle). After the antenna coax was moved to the passenger side of the vehicle, the problem went away.


Perhaps your problem is something similar? Antenna coax too close to the CenCom wires?

 

[Wattco - Brent]

Separate all your power and grounds


Do not run power next to antenna cables


Is there a lightbar on the vehicle - if so what kind?


Have you metered the antenna output? Is it in spec?


You might want to verify the firmware in the Cencom head there were many updates back in the day


Also are your grounds and powers shared on the final install point? As in are they all going to the battery or different locations?