Centracom gold local mic and headset mic both hot

nmfire10 · Post by **nmfire10** » Sun Jul 31, 2005 5:41 am

Is there a jumper or wire on the terminal strip that will fix this on a Centracom Gold? When you use the headset PTT, it also makes the desk mic hot. This makes for a lot of unwanted noises.

Also, where inside the console is the adjustment for microphone gain?

Thanks!
Matt

Will · Post by **Will** » Sun Jul 31, 2005 1:58 pm

Matt, I am thinkging the Mic audio jumper is still in the desk mic, so the desk Mic audio never shuts off in the PTT switch.

nmfire10 · Post by **nmfire10** » Sun Jul 31, 2005 5:44 pm

Yes, the hot all the time jumper is still in place. It has to be. If it wasn't, then there would be no Instant Transmit, general transmit, or foot pedal transmit audio. All those functions rely on a hot mic. If I take that jumper out, the desk mic PTT button would HAVE to be pressed in order to talk.

Before we moved our office, this worked properly. As soon as you plugged the two prong headset cord into the headset jack, it would make the headset be hot and desk mic not. I don't know what is different now though.

Will · Post by **Will** » Mon Aug 01, 2005 1:20 am

OK, my error. Seems the problem may be in the headset jack box or the wiring back to the console. Could the headset in use, plugged in, signal not be getting back to the console?

Some headset jacks are just in series with the mic wiring, had same type of problem on older consoles with butchered headset jacks.

Post by **xmo** » Mon Aug 01, 2005 6:29 am

If by "desk mic" you are talking about the boom mic that Motorola supplies that plugs into CIE main board P10 - OR - the condenser mic built into the front of the CIE, then it should be muted when a headset is plugged in.

If you have some other sort of desk mic connected elsewhere, e.g. CIE aux connector P6 or CIE handset connectors P7 or P16 - then you could have a problem because there are only two mic audio paths in the CIE - one for the main mic input and one for the others [handset, aux or headset]

The path is switched by the "aux enable" signal which normally is asserted when you have plugged in a headset. If that signal was not there - there would be no mic audio from the headset.

If it worked right before it was moved - then whoever moved it foobar'd it. They're the ones that should fix it.

nmfire10 · Post by **nmfire10** » Mon Aug 01, 2005 7:29 am

In our old office, we had the gooseneck mic and it muted when you plugged in the headset.

Now, we have the stupid desk microphone. The desk mic hot, ground, and PTT are hooked up the that connector on the back of the CIE (terminal block that unplugs).

If we move the Desk mic audio path from the P6 aux connector to the P10 mic input on the main board, that should fix it if I'm reading this correctly. I would assume there is no PTT on that, it is just audio so we would need the desk mic PTT to stay on the aux connector?

nmfire10 · Post by **nmfire10** » Mon Aug 01, 2005 10:13 am

xmo wrote:If it worked right before it was moved - then whoever moved it foobar'd it. They're the ones that should fix it.

I did call them about that. They came down and were not having any luck. I'm not sure the tech that was there knew what you just told me about the two audio paths. I left for the day and when I came back the next day it was still not working.

nmfire10 · Post by **nmfire10** » Mon Aug 01, 2005 8:45 pm

I took mic High and Low off the aux connector and put them on an RCA plugged into P10. It's not passing any audio through at all on P10. Is there a jumper or something that disables this input?

Also, there is no condensor mic on the front of the CIE.

Alan · Post by **Alan** » Mon Aug 01, 2005 9:02 pm

If it is a standard Motorola desk mic, it has a jumper inside the desk mic to disable the desk mic TX audio when the mic button is not pushed.

Open the mic by removing the back 4 screws. The front upper cover will pop off. There should be a wire jumper. Cut it. (Note, there may be 2 jumpers, one that makes you push the monitor button in addition to the PTT button to activate PTT and the other is the mic audio jumper).

Once you cut the correct jumper, there should be no desk mic audio until you actually press the PTT button on the desk mic.

Alan

nmfire10 · Post by **nmfire10** » Mon Aug 01, 2005 9:03 pm

nmfire10 wrote:Yes, the hot all the time jumper is still in place. It has to be. If it wasn't, then there would be no Instant Transmit, general transmit, or foot pedal transmit audio. All those functions rely on a hot mic. If I take that jumper out, the desk mic PTT button would HAVE to be pressed in order to talk.

Alan · Post by **Alan** » Mon Aug 01, 2005 11:57 pm

Of course. I didn't think it through.

At this point, I would refer to the manual. It has the jumper/DIP switch settings and schematics to trace the audio flow. The system should have a complete set.

Post by **xmo** » Tue Aug 02, 2005 6:08 am

You can't wire the desk mic into the RCA jack - that input is for the boom mic which is a low devel dynamic type. The desk mic is a high level biased type.

Get your boom mic back.

nmfire10 · Post by **nmfire10** » Tue Aug 02, 2005 7:01 am

xmo wrote:You can't wire the desk mic into the RCA jack - that input is for the boom mic which is a low devel dynamic type. The desk mic is a high level biased type.

Get your boom mic back.

Dag blast it. I can't friggin' win here. At least the pieces are falling together now. The boom mic isn't really an easy option now, as much as I liked it before. There is no good surface to mount it to where it isn't in the way. I suppose I could make something that would attach to the desk between the monitors and the boom mic would attach to that. When we moved, the /\/\ shop took the boom mics back to lala land, i wonder if I can still get them back?

Is there something simple/stupid that I can put on the desk mic that will 'convert' it to low level dynamic?? Seems if such a device exists, it would be easier than building an addition on the console.

Post by **xmo** » Tue Aug 02, 2005 7:39 am

What you need is a desktop dynamic mic.

Maybe this will work:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 5793347308

MOL says it is for the Vortex console and sells for $250.00

Maybe somebody can confirm how this one interfaces - otherwise the ebay price is low enough to take a little risk.

You could also try looking for a desk mounted dynamic mic [like they use for PA systems] at your local pawn shops, music stores, etc.

nmfire10 · Post by **nmfire10** » Tue Aug 02, 2005 9:30 am

I'm not sure that style of mic would really fit in with out equipment (simply by it's look), but at least now I know what I need. I can call Mother /\/\ tommorow and tell them to take back these stupid POS desk mics that they should have never put in to begin with and we'll buy the correct mic for the job. Good thing I didn't try hacking the thing to pieces.

Thanks a ton for the help on this. You know the feeling when if you want something diagnosed and fixed the right way, you have to do the research yourself. Thats how this seems to be going.

Will · Post by **Will** » Tue Aug 02, 2005 2:29 pm

Atlas and other mfgrs make the flex "'gooseneck" mic mounting parts you need to mount your proper console mic(s).

Even RadShack has the goosenecks.

You should be able to extend the leads on the mic if needed with shielded audio coax or even an fe RCA to male RCA connector shielded cable. BTDT !

Alan · Post by **Alan** » Thu Aug 04, 2005 1:41 pm

I came across the following info on this subject:

Please Note: Incorrect documentation in Centracom Installation manual 68-81097E45-O. And in the instructions in the SMR 6476

How to connect a desk top Microphone to Centracom CIE

Install Desk microphone as follows:
1. Remove Gold Desktop CIE top cover by disconnecting the T15 Torx screw holding the ground wire to bottom back left corner of CIE housing. Then slide the two grey latching tabs on the bottom sides forward.
2. On the Desk microphone cut off the four (4) spade lug connectors from the wires. Strip off about 1/4" inch of insulation from each wire.
3. Follow the wiring pin out below for connecting the Desktop Microphone (TMN1005C) to the Centracom Console Interface Enclosure (CIE).

FUNCTION Mic Wire Color CIE P6 CONNECTOR
Monitor White 1
PTT IN Green 2
Ground Silver Braid 5
TX+ Brown 9
TX- Black/Shield 8

4. Note: Connect a 4 inch jumper wire between P5 pin 4 and P6 pin 5. This will enable the Auxiliary microphone connections on P6.

Hope this helps. I don't know if this will address your "hot" mic issue though.

nmfire10 · Post by **nmfire10** » Thu Aug 04, 2005 6:11 pm

Heh. That's exactly how it is wired right now.

Post by **xmo** » Thu Aug 04, 2005 7:06 pm

There are only two [2] microphone audio paths through the CIE electronics.

One is for EITHER the dynamic boom mic OR the front panel condenser mic.

The other path - the "auxillary" path is for ONE of the following: a handset [or handsets with suitable off hook switching], a desk mic, or the headset jacks.

A really good tech - looking at the manual - would realize that the desk mic and the headsets would have to share the second path - which the jumper in the above wiring instructions enables full time.

One solution would be to take the signal from the headset jacks that normally asserts the auxillary input - and wire that to activate an SP relay. Then wire the desk mic audio through that relay in such a manner that plugging in a headset opens the mic audio path from the desk mic, thus solving the problem.