Kenwood TK-931L

The Kenwood TK-931L, like the TK-941L never actually existed. I came up with the idea of swapping the chassis of a 15W TK-931 with a 30W TK-931HD on my first repeater build back in 2007. At the time I was building a repeater using a Motorola STF2520A surplus AMPS amplifier and it required 6-8 Watts of drive. Having a transmitter running continuous duty without added cooling is a bad idea, adding a fan to an exciter is not something I like doing; so after having a few dead and non-salvageable 30W TK-931HD's and a couple TK-930HD's laying around I realized that the chassis of both units were basically identical and that a low power (15W) board could be easily swapped into a high power (30W) chassis.

If you are building a repeater and need an exciter that runs 5-10 Watts, a link radio for your repeater system, an Allstar or Echolink node- without the use of a cooling fan then this project is for you!

Transplanting the TK-931 low power radio into the long heatsink chassis of a high power TK-930HD or TK-931HD can be accomplished in around 20 minutes or less. You will not need to cut, file, or drill anything!

You will need the following Tools:

  1. 40-50 Watt Pencil Tip Soldering Iron with Solder Wick
  2. Phillips Head Screwdriver
  3. Heat Sink Thermal Compound (Zinc Oxide)- This is NOT optional

You will need the following Parts:

  1. One complete low power TK-931 (15W) radio that is tested and working
  2. One high power, non-working 30W TK-931HD or 35W TK-930HD (800MHz) radio. Keep in mind you are only going to be using the long heatsink chassis for this project.

Make sure that you understand that this modification is NOT for people who lack an understanding of how to work with hand tools, small parts, or soldering. Know YOUR limitations and don't try to do this modification if it is beyond your current skill level. YOU HAVE BEEN WARNED!

  1. The first step is acquiring a TK-931HD or TK-930HD long heatsink chassis. These long heatsink chassis are not available from Kenwood, so you will have to find one via the used market. You are looking for a working or non-working TK-931HD or TK-930HD- hopefully you don't want to take apart a working TK-931HD!. Pictured below is the main reason we are going to go with the longer heatsink, the surface area of the TK-931HD/930HD high power radios is much greater allowing for better cooling of the PA module.



  1. I am going to skip all the pictures involved with disassembling both the low power TK-931 and your donor TK-931HD or TK-930HD radio. The chassis swap is very straightforward. You will need to disassemble your TK-931 by removing the display, display gasket, desoldering the chassis mount N-connector, and desoldering the power cables from the main RF board. You will be reusing all parts of your low power TK-931, with the exception of the accesory cable harness and power cable.



  1. With your 15 Watt main RF board out of the short heatsink chassis, remove any traces of old thermal paste from the back of the RF hybrid module (blue brick) and apply a fresh coat of thermal paste. After applying a fresh coat of thermal paste to the hybrid module carefully re-install the main RF board into your new long heatsink chassis- using a few screws to hold the RF board in place. Once the main RF board is in place, install the two screws that hold the hybrid module to the rear heatsink. Once the main RF board is installed, you can re-install the chassis mount N-connector and the power cables- ensure that you get the polarity correct when doing this! Once the chassis mounted N-connector and power cables are re-installed, you can plug in the rear accessory cable to the main RF board, install the pre-drive module and audio amplifier clips. Once these two clips are installed install the VCO shield and RF shield on the bottom side of the radio main RF board. With all the wiring and shields in place install the rubber control head gasket on the front of the chassis, plug in your control head, and secure the control head to the front of your new long heatsink chassis. Before powering on the radio do a final visual check of everything and ensure that everything is where it should be, power on the radio and enjoy your new long heatsink 15 Watt TK-931!