Batboard

gday all , as the topic states, i have had a few of these mics(NMN6191B) now and they all hum when used on xts3000's but not when used with a mts2000? has anyone got a fix for this problem ? thanks

Shadowman

yet again, another five of these mics have come in to my hands and still all of them on every xts3000 we have here hums... nice going moto:P

That is the correct mic for the model. I'd ask your radio service shop to look into the matter and offer for a solution.

That microphone has been canceled, I would look into using current production equipment. Subbed part number is now PMMN4045A. The mics you are using are two revisions out of date and are assuredly several years old... not sure how anyone can point any fingers at this point.

well i believe it uses the screw that tightens it on the unit as some form of earth/grounding ? when the screw is up tight no hum.. when its on loose so we can take the mic on and off with ease it hums. strange i know.. anyway cheers for the input guys:)

Tightening the screw that locks the mic. on the radio also pulls the mic. connector slightly tighter against the radio contacts. If it were me, I would use a deoxide type contact cleaner on both connectors and insure that the "pogos" on the mic. cord still have firm spring tension. Since the problem occurs with multiple mics. I'd be suspicious of the connector on the radio more so than the ones on the mics. Contrary to common opinion gold can also form an oxide coating which is sometimes very hard to spot. Also, if the mic. has been removed and reattached to that radio numerous times, the pogos could have worn a tiny hole in the contact area of the option connector. In any case, it sounds as though you're not getting a good ground to the mic.
Tom DGN

I run NMN6191s on all of my XTS5000s, and the XTS3000s before them. Never any "humming".

tvsjr wrote:I run NMN6191s on all of my XTS5000s, and the XTS3000s before them. Never any "humming".

X2 on that.
Also, almost our entire PD runs those Mics on MTS2000 radios. So, even though these mics are old, they still do a more then adequate job of getting the job done. In fact, I looked up that new PN, I've never seen that mic. in service around my area yet lol We all still use the old "pancake" style jedi mic. (the 6191's and the 6193's).