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Modifications for the Kenwood TM-321

                                                           TM-321A Mars/cap mod


To give the TM321 tx coverage from (142 0r 143, don't remember which) to 151.995 Mhz, remove the top cover.

Look for a loop of wire coming from the display area (the board with the CPU) and going right back.
Cutting this wire and then doing a CPU reset is all you need to do.

Takes about 2 minutes. Be sure that the ends of the wire don't short to something.



                                                  TM-321A Weak mic audio fix


A quick and dirty fix for the knwd tm231a low mic output: knwd comes out with a fix which is to bypass r 63 (3.3K). R 63 and r64 form a voltage divider at the input to the mic amp. R63 is on the bottom of the rig. With the bottom cover off and the front of the rig facing you, locate the mic amp board 3610 which stands vertically off the mother board. Follow the 3rd pin from the left to r63. A jumper here gives the TX audio a nice boost. Be sure to readjust the dtmf output in the mic (the only pot in the mic).



                                  TM-321A Mod to Squelch thw audio at mic pin 6


The following is an easy mod to squelch the audio at mic pin 6 for tnc's

Without true dcd: obtain from Kenwood a 2sd1757(k) (surface mount transistor). Install emitter to mic pin 8, collector to mic pin 6, and jumper from base to the unused pin on connector 202. Using the unused pin rather than running the jumper to the mother board preserves the plug in feature of the front panel.
Connect one end of a 4.7K resistor (I used a 6.8K) to the mute line (ic 5 pin 7), and connect the other end to the unused pin of connector 4, which mates with connector 202. This new circuit is a close copy of the af mute circuit that squelches the rx audio at the speaker. It works perfect with my paccomm micro power 2. The hardest part of the mod is removing the locking ring around the mic connector. I used a modified table fork! good luck.



                                                           Packet mod for TM-321


From: rfc@briar.philips.com (Robert Casey)

The following is an easy mod to squelch the audio at mic pin 6 for tnc's

Without true DCD: obtain from Kenwood a 2SD1757(K) (surface mount transistor). Install emitter to mic pin 8, collector to mic pin 6, and jumper from base to the unused pin on connector 202. Using the unused pin rather than running the jumper to the mother board preserves the plug in feature of the front panel.
Connect one end of a 4.7 K resistor (I used A 6.8 K) to the mute line (IC 5 pin 7), and connect the other end to the unused pin of connector 4, which mates with connector 202. This new circuit is a close copy of the af mute circuit that squelches the RX audio at the speaker. It works perfect with my paccomm micro power 2. The hardest part of the mod is removing the locking ring around the mic connector. I used a modified table fork! Good luck.
        



                                                          KENWOOD TM-321A
                                                         ~~~~~~~~~~~~~~~~~~
ADJ. Controls

VR-1 S-Meter
VR-3 Audio ADJ.
VR-4 RF Meter
VR-7 Low power
TC-1 TX Freq. ADJ.         



All the mods are captured by Packet. 
KB2LJJ    Radio Mods Database 
take now responsibility or liability for any 
damage resulting from this modification.  
                                  

 I have been trying to help our ham radio with the radio modifications and have asked for any type of new radio mods.
 However, I haven't received too many.  If all of you contributed a little more,  I believe I would be able to help 
all the other ham's that are looking for these mods. I know it is possible to get more mods from all the Ham's because of
 the wide range that exist throughout the world.  By doing this we can  flourish and enjoy more of this hobby that 
we've taken part in for so many years. Furthermore, I ask you not to forget to send me any modifications that you might
 have through email.  I would really appreciate it.

      Email                kb2ljj@pacnews.com

 73's
   John Ribeiro
             KB2LJJ