Batboard

I need to do a Maxtrac mod for trunker. Tapped pin 7 and 11 for the discrminator audio, but still need the internal speaker for audio reference. Now, I realize it's a feature that I can't turn the speaker all the way down... but I remember a resistor mod floating around that would allow it to happen. I've been searching the forums and Googling I can't find it!

Thanks for any help!

I have mine set to handset audio to effectively mute it without hardware mods. You could always drill the head and install a switch to put a four Ohm load on it or connect the speaker leads depending on switch position. Or, buy a handset from me if you don't have one. $10 plus shipping+Paypal fees.

Here is a link to my experience converting an 800Mhz unit for Trunker use:

http://batboard.batlabs.com/viewtopic.php?f=1&t=41480

The volume control PC board in the head has a 10 ohm resistor from the low end to circuit gnd. Jumper the 10 ohm resistor and you can then reduce the volume to zero.

Al wrote:The volume control PC board in the head has a 10 ohm resistor from the low end to circuit gnd. Jumper the 10 ohm resistor and you can then reduce the volume to zero.

The surface mount resistor is on the little circuit board with the volume control and Mic jack.

Thanks all for their help! FWIW, here's some pictures to help others.

I'm using a Maxtrac with 16pin board, makes it super easy. I have pins 7 & 11 going to a 3.5mm plug, and 15 & 16 jumpered for internal audio. If you don't want to do any soldering or opening of the radio at all, simply take out the 15/16 jumper and the internal speaker will be silent.

The resistor in the middle is what you have to jump:


You will need HLN9242a. This is the 16pin AMP connector with some pre-pinned wires and an extra set. Most importantly, it comes with the pin extractor!


This is mine... antenna is a Motorola bag phone antenna with mini-UHF connector, SAF4940A (NLA) and just hacked a standard 12v 2A switching power supply. The Maxtrac at full volume pulls about 1.6A.


Hope this eventually helps someone and save 'em an hour of Googling...

Looks pretty good. I like the bag phone antenna...I did the same.

I never used a 16-pin radio in this fashion because I usually rape the logic board to stick in a VHF or UHF radio to upgrade it. My mod was on a 5-pin that I blanked and re-init as 2ch conventional.

I used the phone antenna because I didn't have any other ones!! It was that, or the stock Uniden scanner telescoping one with a mini-UHF to BNC adapter! And well, that just wouldn't be kosher to put Uniden on Moto!

Need speaker for Motorola maxtrac. Used in Fire truck with external only, never had internal.
Limited room in smaller vehicle for bracket & speaker. Just enough space for radio. Tx
Duke