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Microphone Grounding Issue
Posted: Thu Oct 12, 2006 7:57 am
by LT-EMTC9
Hey guys, our ladder truck has a Maratrac A7 in it (that was installed before my time). There are two mics running from it attached on seperate clips. When we lift the mics off the holders, the radio continues to scan, and while they are on the holders, the system "monitors" (even with the monitor button off). I did check out the clips and noticed they are not grounded. Would grounding them cure my problems, or does this look like a programming issue? Thanks!
Posted: Thu Oct 12, 2006 3:09 pm
by thebigphish
it depends on how the radio was originally programmed. If it's set up for it, then yes. There is an incredibly easy way to check it, hold the HUB knob to ground, like a frame screw or the doorframe. (its a quick easy way to check)
Posted: Sat Oct 14, 2006 11:37 pm
by jackhackett
I haven't looked at a Maratrac in a while, but if I recall correctly they need a hang up box with a switch in it and not just a mic clip. There should be HUB and HUB REF pins on the head where the hang up box connects.
From Batlabs Maratrac info:
The pinout of the VIP connector on the A7 head should be something like this:
....
Pin 35 = Hub
Pin 36 = Hub Ref
....
Posted: Tue May 01, 2007 7:19 pm
by bandaidken
Open the mic and jump the contacts....
Everyone stop cringing! It would work fine.
Posted: Tue May 01, 2007 7:33 pm
by tvsjr
bandaidken wrote:Open the mic and jump the contacts....
Everyone stop cringing! It would work fine.
You realize you Lazarused a thread from October '06, right?
Re: Microphone Grounding Issue
Posted: Fri Oct 19, 2007 12:45 pm
by Glen W Christen
I ground the clips and eliminate the issue. FYI, the DTMF mike uses a mechanical plunger to activate an internal switch and does not need a ground.
Re: Microphone Grounding Issue
Posted: Fri Oct 19, 2007 2:07 pm
by tvsjr
I hope the OP has already solved the problem... being a year ago and all.