TDN8305B dtmf mic question

This forum is for the discussions targeted at converting various models of Motorola equipment to operate in the 900MHz Amateur Band.

Moderator: Queue Moderator

Post Reply
The Kreick
Posts: 34
Joined: Tue Jun 07, 2005 6:22 pm

TDN8305B dtmf mic question

Post by The Kreick »

I got this dtmf mic on a GTX mobile & works fine on it... when i put it on a 900 maxtrac the RX audio is very muffled. As the mic connectors between the rigs are *supposed* to be the same, im not sure why it isnt completely compatible on the maxtrac - no manulas at this time to compare prints either - anyone have any ideas?
tnx - ki8hp
User avatar
kcbooboo
Batboard $upporter
Posts: 2117
Joined: Wed May 01, 2002 9:03 am

Post by kcbooboo »

Check the wiring inside the mike. There's a headset signal coming out of the MIC jack on pin 8, and if this gets attached to anything in the mike, it could load it down and cause that problem. The mike itself only needs four wires: mike audio, ground, PTT, and hang-up. These are on pins 3 thru 6, but not necessarily in this order. Most of the 8-pin MIC cords only have six wires on pins 3-8, so trace the end wire and disconnect and insulate it inside the mike.

I recall someone else had a similar problem with a mike that worked on a MaxTrac but not on a GTX, and they found strange wiring in the mike.

See the MIC Jack wiring on the model-specific page for MaxTracs or on the Motorola/MaxTrac page on http://www.repeater-builder.com for more info.

Bob M.
Post Reply

Return to “Converting Motorola Equipment to 900MHz Amateur”