Centracom Gold Elite CIE Console Audio

[paulchristison]

I'm working on four consoles with a wobbling tone in the background of the TX audio when using the gooseneck Mic. Happens on all consoles. Audio is GOOD with the heaset mics. The wobbling can be heard on the logging recorder output of the CIE. I see no level adjustments available for just the gooseneck mic other than JU16 A or B setting and the only option Motorola mentions in the maintenance manual is the A setting. The problem is on one single digital channel only.
Any one else had this problem or have any ideas.

[wavetar]

Probably not your issue, but Gooseneck mic sensitivity can be adjusted via a set of dipswitches, S4, in the CIE. Details on pages 2-2 & 2-3 of the CIE maintenance manual available to me on MOL.

I haven't done any in-depth work on Centracom systems for many years, so I'm just thinking out loud and throwing things out there.

Since the warbling exists at the logging output of the CIE, then it would seem it's getting filtered elsewhere outside of the CIE. Since the analog channels seem fine, perhaps the filtering is taking place in the BIMs? I'm not familiar with what is used in the CEB for a digital channel interface, but perhaps there's a jumper setting in the associated card to help with your issue.

[paulchristison]

looking at the schematic I believe S4 also controls the audio from the headset mic (pins 20(1) and 21(2) on the bottom left half of the schematic sheet 2 of 4 (CIE Maintenance manual). The output to the logging recorder comes out of the CIE after S4 P6(6,7) top center of same sheet. I may try decreasing the sensitivity at one of the consoles on S4 to see if it helps. I am not so sure the noise isn't there on all channels but is much more noticable on the one digital channel.

[d119]

Dumb question, but are all your CIE's grounded back to the CEB? This is critical, and is documented in the Centracom installation manual. It's possible you've got a ground loop somewhere in the CEB or something of that nature.

Since it's occurring on one resource only across all OPs, I'd suggest looking at that resource as Bill suggested, starting with replacing the BIM. All you need to do is set the MUX/BUSY jumpers and TDM address DIP switches of your spare BIM to match the BIM thats in there, and you should be good to go.

Bill: Generally a digital channel in Centracom will consist of a base station (or base station + digital comparator) output to a DIU, which is then interfaced via a BIM/ACIM combination via an AUX II, the BIM handling TX/RX audio between the DIU and the CEB, and the ACIM handling signaling (ID display, Status/Message, Emergency Declarations, etc). Same goes for a digital iDEN resource only the firmware on the ACIM is different, making it an iCIM.

[wavetar]

Bill: Generally a digital channel in Centracom will consist of a base station (or base station + digital comparator) output to a DIU, which is then interfaced via a BIM/ACIM combination via an AUX II, the BIM handling TX/RX audio between the DIU and the CEB, and the ACIM handling signaling (ID display, Status/Message, Emergency Declarations, etc). Same goes for a digital iDEN resource only the firmware on the ACIM is different, making it an iCIM.

Thanks for the quickie description. If you're confusing me with Bill_G, I take that as a compliment, lol.

Todd

PS - good call on the CIE grounding, could very well be the issue.

[Bill_G]

My brother from a different mother!

[d119]

Sorry for the confusion, I smoked waaaay too much crack last night.

(that means a lack of sleep).

[paulchristison]

I talked to Motorola support yesterday. They are recommending relocating the BIM to another slot because of possible interference. I will check grounding before hand and probably try a replacement BIM also. Thanks for the input everyone. I will post the solution when the problem is solved.

[d119]

Let us know what happens. Hopefully it will stop wobbling and stay still.