Intermittent Astro spectra speaker issue - looking for help

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NHfirefighter
Posts: 383
Joined: Mon Jun 05, 2006 4:12 am

Intermittent Astro spectra speaker issue - looking for help

Post by NHfirefighter »

I'm stumped and hope someone may have some thoughts. We have a 110 watt dual control head VHF mobile in one of our fire engines that for some unknown reason has issues where both the front and rear speakers stop transmitting audio. You can see the rx light come on when there is radio traffic however nothing is heard on the speakers. You can however transmit and others can hear your transmission.


I didn't do the original wiring however from what I can see all the proper components were used for the job including an extra long MOL cable to the rear control head. I have swapped the radio drawer out with three other ones and still have the same problem surface. One thing I did notice is both speakers when working have audio regardless of which control head is active. I can't see or figure out why as I thought only one speaker should be active at a time corresponding with the active control head.
Jim202
Posts: 3609
Joined: Sun Sep 09, 2001 4:00 pm

Re: Intermittent Astro spectra speaker issue - looking for help

Post by Jim202 »

NHfirefighter wrote:I'm stumped and hope someone may have some thoughts. We have a 110 watt dual control head VHF mobile in one of our fire engines that for some unknown reason has issues where both the front and rear speakers stop transmitting audio. You can see the rx light come on when there is radio traffic however nothing is heard on the speakers. You can however transmit and others can hear your transmission.


I didn't do the original wiring however from what I can see all the proper components were used for the job including an extra long MOL cable to the rear control head. I have swapped the radio drawer out with three other ones and still have the same problem surface. One thing I did notice is both speakers when working have audio regardless of which control head is active. I can't see or figure out why as I thought only one speaker should be active at a time corresponding with the active control head.


I would suggest that you try some serious trouble shooting at this point. First I would try disconnecting one of the control cables at the radio. it's been a long time since I played with those radios. But I think you have 2 DB25 connectors on the front of the radio. Can't remember which one feeds the front and which one feeds the rear heads.

Anyway, if a cable or speaker might have a short or broken cable, it mat take hours trying to find it. This way you can try by having only one control cable connected and see if the speaker works. I hope it doesn't lock the radio up with a serial error as it might still be looking for the second control head.

If your getting an error, you might have to jury rig a second control cable and control head to do the testing. Either way, it will attempt to point the finger in the direction of the problem.

Like I said in the beginning, it's been a long time working on those radios. My memory serves me to think the RX audio is common to both heads and what one has, the other has. The RX audio starts in the radio with the audio amp and basically is just cable to the speakers. In swapping the radios and still having the problem, you have eliminated the radio. But do the other 3 radios still work normally. You do have a chance to blow the audio output amp inside the radio itself if one of the speaker wires get grounded.
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